
Class _cIifko:r 

Booki^ 



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COPflUGHT DEPOSfT 



TEXT BOOK 



OF 



MILK HYGIENE 



BY 



DR. WILLIAM ERNST 

Official Veterinarian and Director of the Royal Milk Control Station at Munich 



AUTHORIZED TRANSLATION WITH ANNOTATIONS AND REVISIONS 



BY 



DR. JOHN R. MOHLER, A. M., V. M. D. 

Chief of Pathological Division,' United States Bureau of Animal Industry 



AND 



DR. ADOLPH EICHHORN, D. V. S. 

Senior Bacteriologist, Pathological Division, United States Bureau of Animal Industry 

With 29 Illustrations and 5 Colored Plates 



CHICAGO, U. S. A. 
ALEXANDER EGEU 

PUBLISHER 
1914 



<^.. 



4> 



.^H-^ 



Copyrighted at Washington, D. C. 

BT 

ALEXANDER EGER 
1914 



SEP -5 1914 



COMPOSITION, ELECTROTYPINC, PRINTING 
AND BINDING BY THE 
^./-Z> W. B. CONKEY COMPANY 
*^ *^ Hammond, Indiana 

'CI,A37940B 



^ 



Table of Contents 



PAGE 

Translator's Preface • ^'^^ 

Author 's Preface ■ ^^ 

CHAPTER I. 
Anatomy. Pathology and Histology of the Mammary Gland 1 

CHAPTER n. 

Physiology of Lactation and Characteristics of Milk in General 16 

CHAPTER III. 
Microscopy of Milk in General 24 

CHAPTER IV. 
Composition of Milk and Its Biological, Chemical and Physical Characteristics 32 

CHAPTER V. 
Procurement of Cow 's Milk ^° 

CHAPTER VI. 
Internal Influences on the Character of Milk 62 

CHAPTER VII. 

External Influences which Act Upon Milk 132 

CHAPTER VIII. 
Bacteria in Market Milk; Their Origin and Action 152 

CHAPTER IX. 
Milk Control • ; • ^03 

CHAPTER X. 
Milk Inspection • ^ll 

CHAPTER XI. 
Fundamental Principles of Legislative Milk Control. 233 



Translator's Preface 



THE importance of food hygiene in the protection and preser- 
vation of public health is now generally recognized. Milk 
constitutes one of the most important foods for the human 
race, and since its composition and wholesomeness are entirely 
dependent upon its proper handling, the necessity for a strict 
supervision and control is obvious. 

The problem of milk hygiene is very complex and must embody 
all phases of milk control from the time the milk is produced until 
it reaches the consumer. In all stages it may be subjected to 
wilful adulteration and to contamination with injurious and ob- 
noxious substances. Furthermore, the danger threatens this most 
valuable food not only from outside sources but also from internal 
influences, as the milk may leave the animal in the condition of a 
dangerous product, a carrier of pathogenic microbes. Various 
kinds of infection of the udder are frequently important factors 
in the contamination of milk, which would render it dangerous to 
the consumers. Thus in recent years numerous outbreaks of in- 
fectious soje throats have been caused by such conditions. It is 
therefore apparent that in the proper control of the milk supply it 
is necessary to be familiar with all conditions which may be re- 
sponsible for an injurious or unwholesome product. The subject 
is one in which every sanitarian should be thoroughly qualified. 

Although there are numerous splendid publications available 
on this subject, they are either too voluminous to be used as text- 
books or they fail to contain the more recent very important devel- 
opments made in this branch of public hygiene. The excellent 
German publication of Dr. Ernst entitled '^Milk Hygiene" meets 
the requirement of a concise, up-to-date work on that subject, and 
it is with pleasure that in response to requests from various sources 
we have accepted the preparation of an English edition of this 
publication. We did not lose sight of the fact that it should meet 
with the conditions prevailing in this country and accordingly we 



Translator's Preface, 



have iiicliidod much vahial)k^ information from the reports of tlie 

various Milk Commissions, and other sources. For this reason 

Chapter X dealing with German laws and regulations has been 

replaced by Chapter XI which deals solely with the conditions and 

standards existing in this country. 

We cannot refrain from expressing our sincere thanks to Dr. 

H. J. "Washburn for his most valued suggestions and assistance in 

proofreading the manuscript ; also to the publisher, Mr. Alexander 

Eger, for his interest and courtesy during the preparation of this 

volume. 

JOHN K. MOHLER, 

ADOLPH EICHHORN. 

Washington, D. C, July 1, 1914. 



Author's Preface 



THE increased importance of milk as human food demands 
more and more the application of modern accomplishments 
and experiences achieved by science and practice, in order 
to elevate the milk industry to the desired high standard. 

The principal stress must be laid upon production, which con- 
stitutes a special field of the milk industry, and which is most 
generally in. need of elevation and improvement. The product 
will be without reproach only when the conditions of production 
correspond to the value of this food. 

In the field of production, veterinarians are the proper ex- 
perts who must stand by the side of the producers and give them 
the necessary advice and instruction. Only by the active and ex- 
pert aid of veterinarians can it be hoped to improve the good-will 
of the producers ; provided, at the same time, other points of milk 
hygiene which possess bad features — in spite of the active progress 
of milk control and sanitary methods which have been noted for 
many decades — also receive proper attention. 

In order to be able to offer expert advice a thorough knowl- 
edge . of milk, its formation, procurement and characteristics, is 
necessary; likewise, a knowledge of conditions which have an in- 
fluence upon milk while still in the animal body, and the factors 
which change this food after its procurement. These points have 
received the principal consideration in the following chapters. 

In the plan which I have followed, those questions which treat 
of the judgment of milk as human food in relation to its chemical 
contents, were given less prominence. Certain points of this sub- 
ject have been mentioned only to an extent that was considered 
advisable for the general comprehension of the subject. More 
specific questions, as for instance, the preparation of certain milk 
mixtures for the feeding of infants, the advantages and disadvan- 
tages of feeding cows' milk to infants, the action of a milk diet 
in the treatment of adults, etc., are subjects for the ph^^sician. A 



Author's Preface. 



special cliapter on the preparation of infants' milk, or certified 
milk, has been omitted, since the sanitarian can not make any 
distinction in his jndoment of milk as food, hut mnst remember 
that milk which is consumed by children of the masses should also 
come up to the requirements established for any food product 
from a hygienic standpoint. 

The chemical and physical properties of milk are only dis- 
cussed to an extent deemed necessary to instruct the veterinary 
experts in court cases in judg'ino- physiological, pathological and 
external influences. Since the chemical examination of milk should 
be placed in the hands of the food chemist, I have eliminated the 
analytical examination of milk and the examination for preserva- 
tives. For this information I would recommend the numerous 
publications which have appeared during recent times, as for in- 
stance, the works of Grimmer and Sommerfeld, Teichert, Utz and 
Barthel. Only those methods have been described which may be 
undertaken by the veterinarian and which are sufficient for a 
thorough preliminary test of milk for adulterations. 

The illustrations are taken partly from the known works of 
my previous teacher, Professor Dr. med. Th. Kitt (Pathological 
Anatomy) and from Friedberger and Frohner's Methods of Clini- 
cal Examination ; some were drawn by myself. The illustrations 
of apparatuses have been avoided, as they appear in all commercial 
catalogues. 

In dividing the subject into individual chapters repetitions, 
of course, could not be avoided. 

With the preparation of this small work I desire to show to 
my colleagues the road which they must follow in order to cooper- 
ate from a milk inspection standpoint in accordance with the call 
made upon their profession. 

A difficult point of milk hygiene lies in the changing conditions 
of production and not in the control of milk consumption or in the 
supervision of milk transportation. 

W. ERNST. 

Munich, January, 1913. 



Chapter I. 

ANATOMY, PATHOLOGY AND HISTOLOGY OF THE 
MAMMARY GLAND. 

Development and Gross Anatomical Structure. 

In the lowest form of mammalian life a group of glandular 
ducts becomes differentiated from the glands of the skm m the 
median abdominal region. These ducts exude their lacteal secre- 
tions upon tufts of hair of the mammary region, from which it is 
either licked or sucked by the young (duckbill, Ormthorhynchus 

paradoxus). ,^ t ■ ^ i 

One of the land duckbills, the spiny anteater (Echidna hys- 
trix), has lacteal ducts opening within an abdominal pouch 
formed by a fold of skin of the mammary region in the shape of a 
pocket, in which the young are protected and nourished during 
their development. This abdominal pouch is not identical with the 
tegumentarv wall from which is developed the teats of higher 
mammals, but it mav be taken as the point of origin of the different 
forms of teats. In higher marsupial animals the glandular ducts 
are united into a complex gland with teats which constitute the 
orifices of the confluent lacteal ducts. In other still higher species 
the most varied kinds of gland structures are observed with 
various forms of teat development. 

Among the higher mammalian forms the evolution of these 
anatomical structures may be followed during embryonic life. 

On both sides of the body, between the anterior limb-bnd and the inguinal fold, 
the milk-ridge develops from a linear thickening of the ectoblast in the form of a ledge- 
like elevation of the epidermis. Along this milk-ridge a series of at first spindle-shaped, 
then round enlargements appear, which are separated by absorption of the intervening 
portions of the ridge. These enlargements consist of masses of epithelial cells which 
correspond to the anlage, primordium or point of origin of the true mammary gland ot 
the lowest mammalia. This anlage sinks into the underlying mesoblastic tissue and 
becomes surrounded by a proliferating integument, which forms an investment for the 
growing epithelial mass. From this mammary envelope which becomes more or less tlat- 
tended the fibrous and muscular tissue of the areola and teat are derived. At its base, 
solid epithelial sprouts grow out from the sides of the conical epidermal plug, later be- 
coming the lactiferous ducts, while the club-shaped thickened extremities m the further 
course of their development, form the milk sinus. Subsequently, the central part ot the 
ectoblastic ingrowth undergoes degeneration and what at first was an elevation, now be- 

1 



2 Anatomy, Pathology and Histology of the Mammary Gland. 

conies a depression. From the miilillo of this liepressed area there appears an elevation 
that later becomes the teat. 

Ill cattle a single excretory canal enters from the bottom of 
the mammary envelope (point of the teat), into the tissue (the 
milk duct), the end of which, the milk cistern, breaks up into the 
secondary lactiferous ducts. The lower opening of the teat con- 
tains unstriped muscle fibres which act as a sphincter to prevent 
the escape of milk. (Meckel, Kolliker, Langer, Bonnet, Profe, 
Schwalbe, Huss, Gegenliauer, Klaatsch.) 

According to the number of the glandular organs there are 
distinguished the oligomasts and the pol3miasts. Cows are nor- 
mally tetramasts, and usually possess four distinctly separated 
glandular masses, commonly termed the quarters, from each of 
which protrudes a long teat. The four quarters are united to- 
gether in pairs and are arranged s^mimetrically. Between their 
bases and the yellow abdominal fascia they have a rich layer of fat. 

The ndder is attached alon^ the linea alba to the yellow abdominal fascia, and to 
the tendons of the abdominal muscles, by two layers of elastic tissue, the suspensory liga- 
ment (ligamentum suspensorinm niammarum) which penetrates the udder between the 
two halves. 

Although the quarters situated on one side show no visible 
anatomical separation, injection tests with colored gelatin, and ob- 
servations in cases of inflammation of the udder in natural and 
artificial infections have proven that the secretory canal systems 
of the anterior and posterior quarters are separated in the same 
way as those of the opposite quarters. 

These canal systems collect into excretory ducts and terminal 
tubules and finally empty into the milk cistern, which in its iipper 
part is greatly dilatecl and in its lower part is more constricted. 
Each quarter possesses a teat (6 to 10 cm. in length) from the milk 
sinus of which, the duct of the teat (ductus lactifera) of about 8 
mm. in length, passes to the outside. The entire udder is covered 
by fine, slightly hairy skin, which extends posteriorly and supe- 
riorly into the escutcheon or so-called milk mirror. 

The size of the udder varies in the different breeds and indi- 
viduals. 

In the sheep and the goat there are two milk glands, each possessing a teat which 
stands out in a divergent direction from the one opposite. Each teat has one excretory 
duct. While the teats of the sheep are finely haired, those of the goat are hairless. 

The blood vessels of the udder are derived from the branches 
of the external pudic artery and anastomose with the various 
venous branches, through which the blood flows posteriorly 
through the perineal vein into the internal pudic vein and finally 
into the obturator vein. The greatest part of the venous blood 
flows laterally into the external pudic vein and anteriorly into the 
subcutaneous abdominal vein, which forms the immediate continu- 
ation of the external pudic vein and which is known as the milk 



Pathological Anatomy of the Udder. 



vein. It runs bilaterally of the median line, penetrates posteriorly 
and laterally to the xiphoid cartilage of the breast bone into the 
deeper parts and then empties into the internal thoracic vein. 

The lymph vessels which are very numerous enter two large 
lymph glands which lie bilaterally in a depression at the posterio- 
superior portion of the udder and are known as the supramam- 
mary lymph glands. The lymph passes thence to the lumbar 
glands and into the thoracic duct. 

The nerves originate from the lumbar plexus. The udder is 
supplied by the internal branch of the ilio-hypogastric nerve, the 
external branch of the lumbo-inguinal nerve, and the external 
spermatic nerve. In the goat the external spermatic nerve divides 
in the abdominal cavity into three branches, of which the median 
and the caudal branches pass through the inguinal ring to the 
udder. The cephalic branch passes to the abdominal muscles. 
The caudal branch (inferior) is purely a vascular branch. The 
median branch passes to the udder, and ramifies to the milk ducts 
and the teats. 

Pathological Anatomy of the Udder. 

Of the pathological processes which are of importance from 
a practical standpoint, the inflammations and changes which have 
more or less influence on the quality of the milk are of special in- 
terest. The other anomalies will be mentioned only briefly. 

Not infrequently there may be present in cows supernumerary 
teats, or supernumerary milk glands, which may be considered as 
a reversion to early stages in the evolution of cattle. Usually two 
rudimentary formations occur which are generally situated behind 
the posterior normal glands and normal teats. These may at times 
yield milk (Burkart, Dauberton). These accessory glands may 
also occur between the normal teats. In several instances as many 
as four supernumerary teats were observed. 

If the udder is abnormally small in its development or is en- 
tirely absent, it constitutes hypoplasia or aplasia of the udder. 
According to Bosetti the absence of the mammary gland was ob- 
served in a cow two and a half years old. Although there were 
four, small teats on the skin, no milk was secreted even after the 
birth of a healthy calf. The milk veins were well developed on 
both sides. 

The opposite condition, hypertrophy of the udder, with or 
without secretion, is most conspicuous in male animals. Pusch ob- 
served a buck which produced 70 gm. of colostrum-like milk daily, 
and which possessed nipples 7 to 9 cm. in length. Gurlt has re- 
ported that the udder of a steer was as strongly developed as in 
a cow, and produced daily 11/2 liters of secretion. 

It is known that newly born kids and suckling colts occasion- 
ally secrete milk for several days (Gurlt, Martin, Hess, Ibel). 

Schmidt, of Dresden, reported a giant udder with an entirely 



Anatomy, Pathology and Histology of the Mammary Gland. 



normal milk secretion, (16 liters). A functional hyperemia in 
the ])e,^inniiii>- of the lactation period increased tlie four quarters 
unifornily to such an extent that a day after parturition the udder 
touched the .ground with its central surfaces. 

Before and after parturition an abnormal amount of hy- 
peremia occurs physioloii'ically in the udder (hyperemia conges- 
tiva). In inflammations the same condition may be present, the 
capillaries are abnonnally dilated, and greatly distended with 
l)lood. This condition may result in the exuding- of fluid and the 
solid constituents of blood. These are known as capillary hem- 
orrhages. In larger extensions of these liemorrhages they are 
spoken of as sug'gilations, and when the blood is contained in a 
sac-like cavity or swelling it is known as hematoma uberis. 

If in the congestive hyperemia the fluid constituents of the 
blood pass into the tissue of the udder, it results in edema of the 
udder. The same condition may develop as a result of hydremia, 
as for instance after changing from dry to sloppy foods (Bang), 
or as a result of multiple eml)oli of the blood vessels, or from a 
varicose condition of tlie veins of the udder. 

Edema of the udder manifests itself as a soft or tense swellino: of the tissue, which 
retains the impression of the finder. While the teats usually remain normal on account 
of their slight but dense connective tissue, quantities of fluid collect in the front of the 
udder and between its glandular substance and the skin. 

The edema frequently extends posteriorly to the udder and up to the vulva. In- 
fections of wounds with the bacillus of malignant edema may result in edema of the 
utlder. 

To those engaged in milk hygiene the most important of all 
pathological conditions of the ndder are the inflammations which 
result from a reaction of the glandular tissue to any inflam- 
matory irritant. In most instances the inflammations of the udder 
are produced by microl)ian infections of various kinds, particularly 
by poly-bacterial infections. The bacteria penetrate the udder 
either hj way of the blood circulation or from the outside through 
the orifices of the milk ducts. In such cases it is spoken of as a 
hematogenic or galactogenic mode of infection. If the infection 
results from a mixture of bacteria, and is not caused by one kind 
alone, the affection is a mixed infection. Tlie infection may result 
from traumatic conditions when injuries extending into the paren- 
ch^nma of the glands make the infection possible, or from galactif- 
erous-traumatic causes when the infectious material enters the 
milk cisterns upon milking tubes or straws. The infection may 
take place also through simple contact of the orifice of the teat 
with the infectious material. Thus the different forms of mastitis, 
the peracute, acute or chronic inflammations of the ndder may 
arise, depending upon the character of the infectious material and 
upon special accessory conditions. 

The possibility of galaetiferous infection was first experimentally proven by Frank. 
The character and the varieties of inflammations of the udder were further established 
bv the work of Kitt, Nopard and Mollereau, Lucet, Bang, Hess and Borgeaud, Guillebeau, 
Zscliokke, Sven Wall, and others. 



Pathological Anatomy of the Udder. 



The principal producers of mastitis are the colon-paratyphoid 
group, staphylococci, streptococci, Bacillus pyogenes hovis, Bacillus 
tuberculosis, and the actinomyces. 

Colon infection and severe mixed infections usually result 
from galactiferous contact, or after the introduction of milking 
tubes, straws, quills, cat-guts, and hairpins. Highly acute, inflam- 
matory conditions develop in the affected quarters, whether af- 
fected throughout or only partially with parenchymatous mas- 
titis. Hot, painful swellings of the quarters, with collateral edema 

Fig. 1. 




Acute inflammation of the right forequarter with collateral edema. 
(After Kitt.) 

of the surrounding tissues, are the associating symptoms of this 
form of inflammation, which either results in recovery with atrophy 
of the affected parts of the udder, or with regeneration of 
the epithelia destroyed by the disease or on the other hand the di- 
sease becomes chronic and may even terminate with complete gan- 
grenous and ichorous destruction of the affected part of the udder. 

In the iDfectious forms of mastitis the supramammary lymph glands may swell to 
fist -sized nodes. 

If the process becomes chronic a suppurative softening of the 
affected parts of the tissue, or a suppurative demarcation of ne- 
crotic parts of the tissue results. These conditions are designated 
as suppurative and purulent mastitis respectively. 



6 Anatomy, Pathology and Histology of the Mammary Gland. 

The acute forms of mastitis interest those engaged in milk 
hygiene but little, since noticeable changes in the milk quickly fol- 
low the commencement of the inflammation, and the animals soon 
stop their secretion. On the other hand the hidden forms of inflam- 
mation are of the greatest importance because the milk is fre- 
quently almost unchanged, and does not always indicate its ined- 
ible condition. Such conditions of the udder may vary from a 
simple catarrh to a purulent inflammation. The manifestations 
of these forms of inflammation vary to a great extent, and the 
symptoms may be only slightly pronounced, so that a single clin- 




Fibriiious form of parencliymatoiis mastitis; separation of quarters plainly visible. (After Kitt.) 



ical examination may cause a suspicion, but a positive diagnosis 
cannot always be established. 

Literature shows that slightly marked swelling of the affected 
quarters, increased local temperature, nodular formation of the 
parenchyma, and induration of the glandular tissue, may appear 
in the most varied forms, sometimes with and sometimes without 
general symptoms. At the beginning it may be localized around 
the base of the teats, but tlie hardening of the glands then pro- 
gresses forward, upward and backward (Sven Wall). 

Tlie examination of the milk ducts should not be neglected. 
The mucous membrane of the cistern may have become inflamed, 



Pathological Anatomy of the Udder. 



resulting in ulcerations, scar formations or polypoid prolifera- 
tions, which are difficult to recognize. Sometimes such changes of 
the teats are characterized by cicatricial contractions (strictures). 
The udder, which usually becomes affected in the individual quar- 
ters, may remain either normally soft, or may become somewhat 
harder in consistence. The yellowish-red, normal color of the 
cross-section disappears, and changes into a grayish-orange or 
brownish-gray tinge. The parts which are of a harder and tougher 
consistence show an increase of connective tissue ; the interstitial 
connective tissue changes into a bluish-white thickened network. 

Fisr. 3. 




Purulent mastitis showing necrotic foci. (After Kitt.) 



The edema of the skin which develops at the beginning of the 
inflammation results sometimes in extensive sclerosis, even the 
parenchyma of the glands being sometimes dislodged by the pro- 
liferating connective tissue causing the quarter to atrophy and 
harden. 

Tuberculosis although almost invariably resulting from a 
hematogenous infection, appears either in the form of a single 
focus (tuberculosis uberis circumscripta), or it may be dissemi- 
nated over the entire parenchyma (tuberculosis embolica dissem- 
inata), or the tissue may be diffusely affected, becoming infiltrated 
throughout almost its entire extent (tuberculosis diffusa). These 



8 Anatomy, Patholosy and Histology of the Mammary Gland. 



forms of the disease may be present in combination in the same 
udder. During the tuberculous invasion nodular indurations of 
the tissue develop, which hypertrophy and become tense, hard and 
knotty. The lymph glands usually manifest hard, painless, thick- 
eiung, and notlular fonnations. Caverns may also develop in tu- 
berculosis of the udder. 

Actinomycosis which commonly develops from the penetration 
of actinomycotic barley beards, or particles of straw into the 
tissue, or more rarely by embolic infection, may also be produced 
experimentally by the injection of solutions containing actin- 
oniyces through the milk ducts. Actinomj^cosis of the udder has 
been observed in cows by Peterson, Rasmussen, Bang, Harms, and 
Jensen. Nodular formations, connective tissue proliferations and 
softening of the tissues, localized or in larger areas, are also ob- 
served in this disease. 

Botryomycosis and glanders enter into consideration only so 
far as the udders of mares are concerned. 

For completeness, various growths may also be mentioned as anomalies of the 
ndder, such as tibroma, adenoma, adenofibroma, adenocarcinoma, chondrofibroma, chon- 
(h-oma, lipoma, sarcoma, angioma, etc., which are dependent on the tissue elements and 
the character of the tissues of which they are composed. Cystic formations have also 
been observed. 

Not infrequently the connective tissue and the subcutis of the udder of cows may 
show bone formations in the form of liony hooks and plates, (ossificatio plana or 
racemosa). Parasites have also been found in the udders of cows, namely eehinococei 
(Behmert and Steuding). For further information see Kitt, Pathol. Anatomy, 1910, 
Vol. 1, page 280. 

The author once concluded that a goat affected with adenoma papilliferum uberis 
was troubled with mastitis, basing this decision upon an examination of the milk, although 
the secretion contained no speeifie inflammatory agents. The continually increasing 
quantity of milk was remarkable. Postmortem and histological examination finally 
revealed the adenoma in the udder. 

Structure of the Tissue 

The external skin of the teats possesses neither hair nor 
sebaceous or sweat glands, and continues as cutaneous mucous 
membrane into the milk ducts, which it lines up to the cistern. The 
mucous membrane has no glands, possesses fine folds running 
lengthwise, and is covered by pavement epithelium w^hich is 
supported upon a well developed papillary base, and is firm and 
horny next to the lumen. The papillae are extraordinarily long; 
they apparently branch near the base, and slant towards the 
orifice of the teats. This cutaneous mucous membrane of the 
milk duets continues without demarcation, with the mucous mem- 
brane of the milk cistern, which is covered by several layers of 
cylindrical epithelium, and possesses accessory glands whiph are 
lodged in the connective tissue. The wall of the teats contains 
bundles of involuntary muscles running lengthwise and crosswise, 
forming a strong and elastic encasement around the canal of the 
teats. 

The supporting structure is penetrated by numerous blood 



structure of the Tissue. 



9 



vessels and lymph vessels. Numerous and strong elastic fibres 
strengthen the dense fibrillar connective tissue of the teats. 

In order to describe the finer structure of the parenchyma of 
the udder it is necessary at first to touch on the further develop- 
ment of the organ from birth until the moment of the appearance 
of the secretion. 

(a) Normal Appearance. 
The milk gland is an organ which performs increased func- 
tions only at certain times. 



It does not secrete during the entire 



Fig. 4. 




Vertical section through the lower end of the teat canal which is closed by a horny plug (a). 



life but only when the newly born offspring is to be nourished by 
the milk. The udder of a virgin animal does not correspond even 
in its finer structure, with the appearance of a fully secreting 
udder, and this again varies in its finer structure from a gland 
which is at the beginning or at the end of the lactation period ; even 
this is not all, since the microscopical appearance changes in ac- 
cordance with the condition of activity, where a lobule or only a 
part of the lobule may be found on examination, depending 
whether the cell-complex is just forming the secretion or has al- 
ready discharged its secreted product. 

The gland of a newly born calf shows but relatively few cell tubes and cell buds, 
imbedded in connective tissue rich in fat and branching in all directions. These prac- 
tically form the basis of the glandular ducts and are without alveoli. The end of the 
tubes is frequently somewhat dilated, or thickened in the form of a club. 



10 Anatomy, Patliolosy and Histology of the Mammary Gland. 



With puberty the alveoli appear in the cow suriouinled ])y strong connective tissue. 
In older virgin individuals they sometimes show a slight amount of secretion. 

A considerable increase of the glandular tubes appears only- 
after the first conception. The tubes become more dilated and 
branch more and more, forming alveoli, from which other ducts 
bud out. 

Although indications of secretions in the cells may not yet be 
visible, the cavities contain a homogenous or fine granular mass 
of cells or cell fragments. The gland prepares for the secretion, 
growing at the expense of the atrophying or expanding connective 
tissue, until ready to commence its secretion. 



Fig. 5 




Superior portion of the teat canal (a) 'with a reflection of the cutaneous mucous membrane 

of the cistern (b). 



The cell lining of the larger glandular ducts is of double 
layers, as in the cistern, while that of the smaller ducts and al- 
veoli is composed of only a single layer. The epithelium of the 
latter appears cubical or flat, while the upper layer of the former 
is cylindrical; in the deep layer the cells are more cubical and 
rounded, partly wedged in between the bases of the superficial 
cylindrical cells. The borders of the cells are sharp and the proto- 
plasma is clear. The nuclei of the epithelia frequently show mi- 
tosis, that is, division and multiplying forms. The cells rest on the 
so-called basket cells and the membrana propria. The basket cells 



structure of the Tissue. 



11 



should be considered, according to the investigations of Benda and 
Bertkan, as involuntary muscle cells because of their appearance 
and their staining qualities. They probably play a part in the 
emptying of the glandular ducts and the milk secretion. 

Blood capillaries, lymph vessels and nerves run in the inter-and intra-lobular con- 
nective tissue, which is strengthened by elastic fibres, and contains involuntary muscle 
cells. Therefore, the same tissue elements are represented as in the teats, with the ex- 
ception of the many-layered pavement epithelium. 

Fiff. 6. 




Structui-e of the mammary gland in secretion, Hematoxylin. 1 X 800. 
(a) Secreting glandular alveoli. (b) Alveoli with dormant cells. 

At the end of pregnancy the picture again changes consid- 
erably. The protoplasm of the previously clear epithelial cells of 
the secretory system becomes cloudy, the nuclei larger, their chro- 
matin collects in flakes on the periphery of the nuclei, the borders 
of the cell become indistinct, the cells become swollen, the nucleus 
lies_ in the center, and the indications of the division by indirect 
fission of the nucleus appear relatively in groups. Some epithe- 
lial cells show two nuclei at this stage; towards the alveoli fat 
globules appear. Leucocytes with which a few eosinophiles are 
mixed, collect beneath the epithelial cells and penetrating the 



12 



Anatomy, Pathology and Histology of the Mammary Gland. 



epithelial layer, separate themselves from the epithelial cells and 
enter the alveoli, which at this stage contain fatty secretions, 
leucocytes and epithelial cells in all stages of degeneration. 

A\'itli these manifestations the gland cell connnences its 
function. The desquamation of epithelial cells and the cell de- 
generation disappear; the cellular infiltration of the connective 
tissue recedes until it is very slight between the now greatly di- 




Chronic mastitis of cow. 1 X 800. 

(a) Thickened interstitial tissue. (b) Alveoli. (c) Bloort vessels. 

(1) Epithelial desciuamation. (2) Colostral bodies. (3) Cellular infiltration. 

(4) Fatty degeneration and necrosis. (5) Milk concrement. 



lated and distended glandular ducts. The cells are finely granular 
on the basilar border, and at times show striation, that is, fine 
streaks running in parallel directions (bioplasts according to 
Altmann). 

The nucleus is large and vesicular in shape; the upper part of 
the cell is granulated and shows large and small fat globules. This 
granulation and streaking may be seen, according to Steinhaus 
and Duklert, at each act of secretion. The fine fat globules collect 



Structure of the Tissue. 



13 



into larger ones, which are only separated from the lumen by fine 
protoplasm, or having been expelled have already entered the al- 
veoli. With the collection of the secretion these dilate, the cell 
becomes flattened during the expulsion of its products, and the part 
lying towards the lumen appears indistinctly bordered as if 
shredded after the expulsion of the fat. They soon become smooth 
again, and by the pressure of the alveolar contents and the dilation 

Fig. 8. 




C'lronic mastitis of cow. 1 X 90. 
(a) Healthy portion, (b) Glandular portion with chronic mastitis. 

of the alveoli, the cells sink and become so flat that the nuclei not 
mfrequently appear bulged out towards the lumen. After the 
expulsion of the secretion the formation of additional secretion 
again commences in the cell, the protoplasm again becomes cloudv 
and granular, and so on, a continuous change of the form of the 
cell taking place. 

During the entire lactation period, but more so in the later 
stages, manifestations of atrophy of the gland appear, at first 



14 



Anatomy, Pathology and Histology of the Mammary Gland. 



commencing at the base of the gland, and finally during the end of 
lactation in the entire ndder. Epithelial cells are thrown off, the 
alveoli become fewer, smaller, and irregularly distended, the con- 
nective tissue increases, and cellular infiltration starts under and 
between the epithelial layers. The epithelium contains no fat 
globules, it is sharply bordered towards the alveoli and the pro- 
toplasm becomes pale. Finally the last remains of the secretions 

Fig. 9. 




Acute streptococcic mastitis of sheep. 1 X 1000. 

(a-1) Blood capillaries. 2. Thrombosis by disseminated streptococci. (b) Glandular 

alveoli, with clumps of streptococci. (c) Migration of leucocytes into 

the infected alveoli. 

disappear, the plasma cells and leucocytes taking care of the 
resorption. 

At the end of this process the gland is at rest, and the cow is 
dry. 

Of course these processes are not always so schematically uni- 
form as they have been described. During the entire lactation 
period, colostrum-forming, and retrogressing lobules may be ob- 



structure of the Tissue, 15 



served; likewise certain parts of the udder may remain in secre- 
tion during retrogression until storing of the secretion, leucocytio 
resorption activity and connective tissue proliferation cause them 
to cease their activity. 

(b) Pathological Appearance. 

Any kind of irritation of the gland, such as stasis of the milk, 
especially in chronic catarrhs and inflammations, may result in the 
most varied kind of pathological conditions, either in mixed form 
or individually. The manifestations vary, depending upon 
whether degeneration and destruction of the tissue, or reparation 
and recovery gain the predominance. 

Sometimes desquamation of epithelium, with or without fatty 
degeneration, occurs together with cellular infiltration of the in- 
terstitial connective tissue and capillary engorgement as the only 
indications of inflammation ; or, on the other hand, the changes in 
the interstitial parts may be very pronounced, while the changes 
of the parenchyma may be less prominent. The inter- and intra- 
lobular connective tissue extends forming thick indurations, from 
which the separated epithelium is compressed to small necrotic 
nests. In other stages of inflammation the cellular infiltration of 
the tissue predominates. The alveoli and the milk ducts are 
plugged up thickly with leucocytes, and dilated with the pus. In 
highly acute inflammations the rapid breaking down of cells, de- 
struction of epithelium, serous and cellular infiltration of the 
tissues even to their dissolution, are the principal manifestations. 
The ducts and the alveoli are inundated with serous, bloody co- 
agulated masses. 

In stasis of the milk, and in all inflammatory manifestations, 
especially of the acute form, the alveoli contain hyalin and con- 
crement arranged in layers, in addition to inflammatory cells and 
broken down cellular products. 



Chapter II. 

PHYSIOLOGY OF LACTATION AND CHARACTERISTICS OF 

MILK IN GENERAL. 

As already mentioned the udder secretes only in certain 
lactation periods between births. The lactation lasts under nat- 
ural conditions in healthy animals as long as the young needs 
the glandular secretion for its nourishment, and stimulates the 
lactation by the irritation of the intermittent suckling. Shortly 
before parturition, or at the time of parturition, the glandular 
tissue terminates its increase in development, and the milk secre- 
tion starts and becomes actively established. 

The causes of the increased cell production during pregnancy, 
and for the secretion after this time, are variously explained. 
Nervous irritation from the genitals to the milk glands may by 
means of reflex action stimulate the glands into activity. 

That such reflexes on the genitals may originate from the 
milk gland is proven (Pfaundler). Reflex actions in the opposite 
way, however, have not been proved (Halbau). 

It has been impossible either experimentally (extirpation of 
the lumbar cord) or by accident (fracture of the spine), to pro- 
duce a complete ''nervous isolation," since as emphasized by 
Pfaundler, there are still remaining the nervous connections 
through the vasomotors. However, the re-section of nerves, oper- 
ations on the spinal cord, transplantation experiments, etc., by 
Eckhardt, Rolirig, Sinety, Busch, Mirnow, Pfister, Ribbert, Golts 
and Ewald would suggest that besides the nervous influences, 
which undoubtedly exist, there must be some other agent which 
stimulates continuous growth during pregnancy, terminates the 
same with the end of parturition, and inaugurates the secretion. 

Hematogenic influences may be readily accepted, as they may 
be led to exert their action either by the quantity or by the quality 
of the blood. 

After parturition the 1iody and the milk gland have at their 
command great quantities of blood Avhich was previously utilized 
by the gravid uterus. The plethora which appears at this time 
may be held responsible for the inauguration of the secretion, 
after the udder has been rendered ready for action by the increase 

16 



Milk Secretion. 17 



of its growth tlirougli nervous influences. On the other handit 
has been observed that in other conditions, in which there exist 
also a diversion of great quantities of blood from the genital parts 
for the supply of other organs, as for instance after operation on 
very large tumors in the region of the genital organs, no. secre- 
tion appears even when the udder is prepared for the secretion. 

As a matter of fact the secretion may commence before birth, 
and even in early abortions, or if the fetus dies. At times when 
the uterus is only so slightly distended that the quantity of blood 
set free after abortion is hardly sufficient for an effective hypere- 
mia of the milk gland, the secretion of milk may result (Smety, 
Kreidl, Mandl). Therefore the explanation that the quantitative 
influences of the blood may give rise to a stimulation of the milk 
secretion (Freund), can scarcely be accepted. Consequently the 
qualitative changes of the blood must be considered as more prob- 
able factors. 

Authors have diversified opinions upon this question. 

While some accept the view that substances are eliminated 
from the impregnated organs, or by the fetus itself into the blood 
of the mother by internal secretions, and that these act as stimu- 
lants on the milk glands, others believe that the factors causing 
lactation lie in the assimilation of certain nutritive substances. 

The supporters of the theories of ''stimulation substances" 
(Sinety, Halban, Starling) take the stand that stimulating sub- 
stances which cannot be utilized for the cellular growth and cellu- 
lar activity, contrary to the nutritive substances, cause the devel- 
opment of the gland during pregnancy, and at the same time pre- 
vent it from secreting (stimulines, hormones [I stimulate], sub- 
stances of pregnancy). Development of the gland and prevention 
of secretion may, of course, be the action of one and the same sub- 
stance (Hildebrand, Starling), or its development, as long as the 
growth continues, may retard secretion. With birth the stimula- 
tion of growth and development ceases, and secretion commences. 

Contrary to this, the theories of nutritive substances empha- 
size the fact that the glands at times may start the specific activity 
without the presence of certain stimulines, probably through nutri- 
tive substances which are present in the blood at various times. 

Eauber attempts to explain the activity of the gland after 
birth by declaring that after the expulsion of the fetus a nutritive 
material becomes available, which has served prior to birth for 
the preparation of nutriment for the offspring. While the ex- 
planation of the author that the lymph cells play the most impor- 
tant part in this can no longer be considered, still it furnishes 
the basis for all new theories relating to the action of nutritive 
substances. 

These views were streng-thened in 1908 by Schein by the state- 
ment that during pregnancy the mother animal, in order to meet 
the requirements of the fetus and of the impregnated organs, en- 



2 



13 Physiology of Lactation ami Cliarat'teristics of Milk in General. 



riches lier blood with the so-called "milk producing substances." 
Pfanndler recommends the designation " offspring- nutritive pro- 
dncing substances." Since during pregnancy the continuously 
developing placenta utilizes and consumes these sujjstances for use 
in the nourishment of the young, there remain for the milk gland 
only slight remnants, just sufficient to result in the necessary stimu- 
lation for the cellular increase in the gland. After parturition 
Avhen the activity of the phieenta is completed, the milk gland takes 
up the released nutritive sul)stances for its own use (specific af- 
linity of the substances to the cells of the milk gland), and is 
stimulated to secretion by the quantity of the disposable material. 
Sehein's milk producing sul)stances in the blood constitute the 
initial material for the formation of specific components of the 
milk, milk sugar, casein and milk fat. 

The material acquired by the mother, through placental con- 
tact with the fetus, while aiding in the development of the latter 
is also of benefit to the activity of the milk gland, whose product 
adapts itself exactly to the requirements of the young, as far as 
it concerns the material which the young uses for the growth of 
its body. 

If conception again takes place the developing placenta of 
the new fetus enters into competition with the lactating gland, and 
draws from it milk producing substances for its own use, whereby 
the secretion of the milk gland becomes reduced or ended. 

Influences exerted on the milk gland by oestrum or puberty, 
and also the impulse of pregnancy, have not yet been sufficientiy 
explained through this theory. Pfanndler enlarges upon and ex- 
plains these phenomena by stating that the withdrawal of certain 
nutritive substances, through the germinal gland, embryo and 
ovum, and not the appearance of milk producing substances alone, 
periodically disturb the equilibrum of physiologically acting sub- 
stances in the blood, and thereby the antagonizers of those sub- 
stances (the stimolines, harmones of other authors), are enabled 
to find specific receptors (affinities) in other organs of the genital 
apparatus. 

After birth, continuing intermittent stimulation may retain or 
increase the lactation of the milk glands for a longer or shorter 
time. Stasis of the milk diminishes and retards the secretion. 

Rievel opposes Schein's view, since in his opinion it does not 
explain how udders of animals in which neither pregnancy nor 
birth has preceded, could start secretion (lactation of milk glands 
of the newly born or virgins, occasionally even of male animals). 
According to the author's view these facts would not oppose the 
theory of nutritive substances. Schein, himself, aims to bring 
these observations into harmony with his views, and asserts that 
the newly born ma}^ give a secretion from their milk glands, when 
towards the end of pregnancy the activity of the placenta is dis- 
turbed, and as a result small quantities of the ''milk producing 



Milk Secretion. 19 



substances" enter without changing directly into the blood of the 
fetus, and thence into its milk gland. Sufficient stimulation for 
the secretion and formation of the so-called "witches milk" re- 
sults. Schein explains the formation of milk in virgin mammae, or 
in milk glands of individuals which have passed their climacteric, 
by the fact that through the stimulation produced by sucking, the 
secretory cells are awakened from their dormant state and then 
utilize the milk producing substances in the blood for the perform- 
ance of their functions. Finally (1910) he concludes that the oc- 
currence of milk secretions in nullipera and in women who have 
passed the climacteric, which differs from the gradually inaugu- 
rated normal lactation as a result of pregnancy, and also the ob- 
served secretion by the breasts of newly born and of male indi- 
viduals, represents a continuous secretion analogous to the normal 
secreting process in other glands, in which the product is as a rule, 
however, re-absorbed by the glandular elements. In pregnancy and 
at birth the secretion is increased to the greatest extent, but other 
stimulants may under certain conditions stimulate the activity of 
the gland. Duval's more recent observations contain data relative 
to the occurrence of milk secretion by women outside of their 
normal lactation periods. 

It is not uncommon to observe secretions in virgin animals 
especially when young animals which are present stimulate the 
udder intensively by sucking. It should be emphasized however 
that the udder secretion of virgin animals distinguishes itself in 
its appearance from the milk of mature milking animals ; it repre- 
sents a secretion which does not even deserve the name of milk. 

The experiments which were conducted by various authors 
in support of their lactation theories appear of interest. 

The experiments of Starling aim to show the presence of 
bodies in the blood during pregnancy which prevent secretion, in 
which claim is made that an interruption of pregnancy in rabbits 
at a time in which alveoli capable of secretion were not yet present, 
led to a retrogression of the milk gland, while in the later periods 
of pregnancy secretion was induced. 

According to Pfaimdler's view the harmone theory could be 
effectively supported by the fact that an existing secretion may 
be successfully interrupted or prevented by the introduction of 
serum of pregnant animals of similar species. 

The author does not believe that this proof is satisfactory and 
mentions observations made in a case in which the secretion ap- 
peared at birth of twins which were born at long intervals, that is, 
the pregnancy continued after the first birth, yet the milk secretion 
continued unchecked. Wucherer observed a case in which a sow 
gave birth to nine, and seventeen days later to six other pigs. At 
the birth of the second lot the first born pigs were taken from the 
sow. These continued to thrive, but of the second lot only three 
remained alive. He emphasizes the opinion that a transitory 



20 Pliysiolotry of Lactation and Characti'ristics of ]\Iilk in General. 

action of blood serum, as used in Pfaundler's experiment, which 
corresponds only slightly in its composition M'itli the normal blood 
serum, can never be favorably compared with natural influences 
in the body. This exception must hold also for the indecisive ex- 
jjeriments of Starling-, who by injections of juices from rabbit em- 
bryos, but not with injections of preparations from rabbit ovaries, 
placentas and mucous mend»rane of the uterus, produced a devel- 
opment of the glands, and at times a degree of milk secretion. He 
believes that tlie true cause of the secretion may be found in the 
chemical changes which are produced by the growing embryo and 
are brought to the glands through the placental circulation. Ac- 
cording to Basch, secretion may be establisluMl in the mammary 
glands of virgin rabbits b^^ injecting them with placental extract 
(serum of unlike origin, from man), which was so powerful that it 
also brought on a secretion of milk in mother animals without the 
intervention of pregnancy. The placental extract could induce the 
secretion only when the teats of these animals were stimulated to 
hyperplasia by the implantation of ovaries from pregnant animals. 

According to the author's observations these questions can 
only l)e determined through experimentation, when by uniting two 
female individuals of like species a basic condition is established, 
by which the activity of the glands of one of the impregnated indi- 
viduals as a consequence of its pregnancy may be observed upon 
the other, and the result of the impregnation of the latter on the 
lactation of the first mother may also be determined, Such experi- 
ments have already been made by Cristea of Vienna, by celiotomy 
of a virgin and a pregnant animal, and uniting both by suturing of 
the peritoneum, the musculature and the skin, the author establish- 
ing a double individual, united by a broad peritoneal communica- 
tion. Of eighteen such pairs (rats and rabbits) six remained alive. 
In the experiments after parturition of the gravid animals the milk 
secretion also appeared in the virgin animals to which they were 
united. Cristea therefore believes in a slow transition of a secretion 
from the gravid animal into the non-impregnated animal, namely 
by the way of the lymphatics, since there existed no blood vessel 
union between the individual animals. With this result the hypoth- 
esis that the changed distribution of the blood after birth pro- 
duces the milk secretion collapses, since on account of the lack of 
communication of the blood vessels it is not possible that an in- 
creased blood supply of the mammae of the virgin animal would 
result from parturition of the attached animal. It can make no 
difference whether milk producing substances or substances which 
are not assimilable and are not consumers of energy (stimulating 
and inhibiting substances), stimulate the glands to activity. 

Eecently Basch observed an abnormal birth to one of a pair of 
twins (the Blazek sisters showing a condition of pygopagus, union 
of the pelvis and sacrum with a common introitus vaginae, and a 
common rectum), in which after the birth of a child to one, lacta- 



Milk Secretion. 21 



tion commenced also in the virgin sister. In this instance nervous 
connections may exist in the genitals of both individuals. Accord- 
ing to the author's view this case is not an absolute proof of the 
stimulation of the gland by hematogenic means. 

The lactation theories may be laid aside, and consideration 
only be given to the fact that at birth, puberty, pregnancy, at the 
conclusion of parturition and also in the disturbances of the gen- 
itals influences are exerted on the milk gland the character and 
action of which are still uncertain, although the results manifested 
by the production of milk may readily be observed. Especially 
typical and striking are the phenomena seen at puberty and during 
and at the end of pregnancy. Exceptionally a condition may ap- 
pear outside of these normal periods of the organs in females, and 
in single cases even in male individuals, which permits the conclu- 
sion that the glands react to special stimulation. Abnormalities 
may occur in the anatomical structure of the gland, pathological 
manifestations in the sense of inflammatory reactions, etc., may 
also be observed, and exceptionally the usual functions may be 
present or may develop, without their being accompanied by gross 
anatomical changes of the gland ; these however are usually pres- 
ent at the same time. 

These influences on the gland originate partially in the gravid 
genital organs and the fetus; in other instances the germinal 
glands and the disturbances of their functions are the cause of 
these influences. 

Such influences may be classed according to the impulses 
which lead to glandular activity, as follows (Halban) : 

1. Embryonic impulse — action very transitory — ^mastitis 
neonatorum — witches milk. 

2. Puberty — lasting effect — development of the gland. 

3. Oestrum — action rapidly transitory — ^hyperemia, inter- 
stitial hemorrhages, disturbances to physiological lactation, secre- 
tion. 

4. Impulse of pregnancy — lasting between parturitions. 
Lactation may be sustained for a long period of time by the 

regular drawing of the milk, and ceases in healthy udders only 
when after frequent and absolute stasis of the milk (after about 
eight days), the tissue becomes affected by inflammatory irrita- 
tions (absorbtion and change of the condition of the epithelium), 
or when the animals are soon to give birth to young. If no re-im- 
pregnation takes place the lactation period may last longer, even 
from one to two years although not to an unlimited extent. The 
activity of the gland may be retained for a long time through the 
sucking of the young, stimulation by milking, or artifical with- 
drawal of milk. 

Frequent periodical and complete emptying of the milk cis- 
terns acts favorably on the amount produced. In the cow two to 
three milkings per day are sufficient to retain the udder in secretion. 



22 Physiology of Lactation and Characteristics of Milk in General, 



The milk formation occurs between the milking- periods and 
during- the milkings; therefore of these two periods, the first lasts 
for many hours, the second with more intensive production is com- 
pleted in a few minutes. The first phase is the work of continued 
activity of the gland, the second is brought on under the stimula- 
tion of the sucking, or milking, on the secretory nerves, and as a 
result of the increased blood supply (stimulation of the vasodila- 
tors). The capacity of all the milk ducts of the udder represents 
less than half of the quantity of milk obtained in one milking. 

According to Fleischmann the volume of the entire udder of a 
cow with the teats is 6700 c. c. Of this 3000 c. c. is represented 
by the cavities ; the secretion obtained in one milking may never- 
theless amount to 7000 c. c. 

Niiesch substantiates Fleischmann 's statements by an experi- 
ment; a cow gave daily before slaughter 10 liters' of milk of 
which 5 . 5 liters was the amount of the morning milking. 

After slaughter before milking in the morning 2.7 liters of 
milk could be proven in the ndder (catheterization and calculation 
of the amount remaining in the udder), which proves secretion 
during the process of milking. 

The two phases may be considered as though the glandular 
cells which tire after the milking gradually recover (increased 
blood supply) and recommence their secretions. The collecting 
secretion will increase until a certain relative pressure between 
the collective quantity of secretion and the tissue with the blood 
vessels is established, when the secretion is retarded or ceases until 
renewed stimulation of the glands by milking, emptying, massage, 
(electric irritation), or stimulation of the central nervous system 
from milk accumulations causes the milk to till the cavities of the 
udder again. 

If the usual milking time is omitted a flow of milk may result, 
that is the pressure under which the secretion is held finally over- 
powers the resistance of the sphincter mnscles at the opening of 
the teats (directly or by reflex), whereupon formation of milk 
again takes place. 

Nervous influences on the secretion are exerted by the sper- 
maticus externus and by the sympathicus. 

Experiments which were conducted for the study of the ener- 
vating influences on the secretion produced contradictory results. 

Rohrig severed the ramus inferior of the nervus spermaticus 
externus (vessel branch), and observed an acceleration of the 
secretion, while the severing of the glandular branch (part of the 
median branch) resulted in inhibition. Eckhard failed to observe 
any influence on the quantity of milk after the severing of the ner- 
vus spermaticus externus. Heidenheim and Partsch demonstrated 
an increase of the quantity of milk from the cutting of the nervns 
spermaticus externus, but only when strychnine or curare had been 
administered at the same time (test by Sinety on guinea pigs). 



Milk Secretion. 23 



Although Bagch could not establish a quantitative increase by sev- 
ering the nervus spermaticus externus, he found qualitative 
changes (formation of colostrum). 

Pfaundler concludes from these and other experiments that 
an action of the peripheral nerves on the development of the gland 
and its functions, especially from a qualitative point of view, must 
figure in the consideration, but that these influences have only slight 
importance. 

Insignificant as well in their results on the secretion were the 
severing and re-sectioning of the spinal cord, or interference with 
the sympathetic system. Basch again observed the formation of 
colostral milk after re-sectioning of the coeliac ganglion. From 
this he concludes that the regulating influence of the nervous 
system exists through reflex action, especially from the sympa- 
thetic, but that at the same time the gland is also capable of 
independent secretion. 

As a matter of fact far reaching influences of a nervous 
character are observed. 

1. Psychic influences. 

2. Eeflexes, which are caused by local stimulations (sucking 
— ^milking — electrical stimulations, etc.). 

3. Eeflexes from the genital region. 

These points are only briefly mentioned here, since the various 
conditions will be discussed in subsequent chapters, when consider- 
ation will be given to the quantitative and qualitative changes 
which appear under varying influences. 

An active part in the emptying of the milk from the cisterns, 
and in the passage from the upper part of the duct and alveolar s^^s- 
tems, is played by the sucking and pressure exerted during the 
milking (pressing outwards, sucking from the gland), massage of 
the udder (pressing out into the cistern), the contractility of the 
tissue (elastic fibres, involuntary musculature, filling of the blood 
vessels), and the vis a tergo of the newly formed secretion. 



Chapter III. 

MICROSCOPY OF MILK IN GENERAL. 

If milk is examined tlirougii a microscope one chiefly sees 
nnmerons small fat cells floating in the fluid or milk plasma. These 
will be considered later, but at first the cells and cell fragments 
originating from healthy and affected udders will be discussed. 
Between the milk globules, by which term the small fat droplets 
are designated, bodies may be seen which are hard to define unless 
stained. After special treatment, however, they may be readily 
recognized as cells or their fragments, or as a precipitation of 
soluble or suspended substances. 

Since the external skin of the udder, and the lining of the milk 
passages and milk secretory ducts in the udder are of similar for- 
mation, we naturally are only concerned with the upper layers of 
pavement epithelium, cylindrical epithelium, and the deeper cubical 
epithelium of the terminal ducts and alveoli, and only in severe 
tissue changes would cells of other parench^niiatous parts appear 
in the milk. Naturally in such an actively working organ, even in 
a physiological normal condition, leucocytes of the most varied 
kind, and even red blood corpuscles may be found. In cases of 
special stimulation from physiological or pathological causes, the 
resulting cell mixture may be of a most varied character depending 
upon the location of the stimulation, and its quality and duration ; 
hence at times certain leucocytes, and again reel blood cells or 
epithelia, may predominate in the mixture. 

1. Cells from compound pavement epithelium. Following 
the intensive manipulation and stimulation of the teats by milking, 
the appearance of cells from the upper layers of the pavement 
epithelium of the outer skin, and the milk duets is natural. As 
a matter of fact in the fresh milking periods during which irrita- 
tion from the extraction of the milk is especially evident, the 
milk always contains fine folded platelets of round, oval, or irreg- 
ularly distended and curved borders, which frequently when folded 
in several layers, appear as small clasped cysts without special 
structure. 

These bodies have been described by Winkler, and were con- 
sidered by him as indications of pathological changes. The author 

24 



Cellular Content of Milk. 



25 



took a stand against this view of Winkler, as he had observed them 
in the milk of entirely healthy animals, but not until the present 
time has he been able to offer an explanation of the nature of these 
bodies, designated as "skinlets" or "shell." They represent 
desquamated cells of the stratum mortificatum of the pavement 
epithelial layers singly or in groups. Although usually no parti- 
cular structure is manifested yet in single instances typical flat, 
round nuclei can be seen. 

If the teats of a slaughtered cow are taken and the cistern and 
milk duct are carefully cut open, and from the surface of the milk 
duct a small quantity of the 

cellular layer is scraped Fig. lO. 

off, an examination by the 
usual method discloses the 
typical "shells." 

2. If cells from the 
cistern are prepared and 
examined, elongated or 
oval, or quadrangular cells 
with oval nuclei, frequent- 
ly elongated at the base, 
will be found, singlj^ or in 
groups. Single fat drop- 
1 e t s may frequently be 
seen in the plasma sur- 
rounding these cells. Sim- 
ilar cells may also be found 
in normal milk. They are 
usually single, although 
sometimes united in 
groups arranged like flow- 
ers. In stimulation, which 
brings on a desquamation 
from the mucous mem- 
brane of the cisterns, or 
from the parenchyma in 
catarrhal conditions of the 
milk passages, they of 
course appear in masses. 

Such reactions occur in the cistern for instance as a result of 
the so-called kneading. 

3. Cells from the secreting milk ducts and the alveoli, ap- 
pearing large or small according to the quantity of fat globules 
collected in them, often become tremendously distended and bloated 
(foam cells). Their structure is mostly honeycombed or mulber- 
ry-shaped when they contain fat ; without fat the cell is surrounded 
with only a narrow'border of protoplasm. The nucleus is usually 
in good condition. 




Film of sediment from milk of a fresh milking cow. 

Cells from the stratified layer of pavement epithelia 

of the teat canal. Thionin. 1 X 1000. 



26 



Microscopy of Milk in General. 



Fi-. 11. 



These cells are tlie lar^e colostral bodies. They are in their 
entire structure and in their stainino- eharacteristic epithelial cells 
and not leucocj'tes; the amoeboid movements observed in them, if 
these observations were beyond questioning, do not prove that all 
colostral bodies represent leucocytes. 

This point will be again taken up during the discussion of colos- 
trum. While such cells only appear occasionally in ripe milk they 
are extremely numerous at the beginning and termination of secre- 
tion, and in pathological processes, in the latter especially in sul)- 
acute and chronic forms, butnotin peracute and acute inflammatory 

conditions of the paren- 
chjqiia. Such cells may 
occasionally be noted 
collected in groups. 

The author believes 
tliat their appearance in 
masses in the milk, that 
is, the condition increas- 
ing the expulsion of 
these epithelia, results 
from the fact that each 
cell, which in its singu- 
lar activity precedes or 
follows the other cells 
of the union, becomes 
desquamated. It does 
not correspond func- 
tionally, with the other 
cells, and is therefore 
removed from the rows 
of cells which are de- 
veloping for a definite 
purpose or are working 
for that purpose. Only 
Avlien uniform work is 
performed by all of the 
cells working in unison, 
and bringing about a 
uniform condition, will the organ cease to free itself of incapable 
elements. In inflammation the inflammatory irritation and its 
consequences soon drive the cells to overproduction. At other 
times it paralyses or destroys them, even before the formation 
of milk, depending on the duration of the inflammation. 

The form of the epithelium varies in accordance with the con- 
tent of fat. The collection of fat is not the result of fatty degenera- 
tion, but is produced when the cell is thrown off before its time for 
secretion, or while still capable of taking up material and produc- 
ing fat but without strength for the separation of fat. Therefore 




Cells from the lining membrane of the wall of the cistern. 
Sediment in catarrh of the cistern. Thionin. 1 X 1000. 



Cellular Content of Milk. 



27 



Fig. 12. 



such cells may be found even in the epithelial groups, which is an 
additional proof that they with certainty represent epithelial cells. 
The cells are from 5 to 25, even to 47 /* in size (Schulz). Not 
infrequently 2 to 3 nuclei of oval or roundish shape are present. 
The author has never observed more than one nucleus, and be- 
lieves, with Popper and Schulz, that the appearance of more than 
one nucleus results from two cells lying on each other, in which 
case the cell thus formed may appear to possess two or more nuclei. 
Migrated macrophages may also simulate a polynuclear 
appearance. 

Not infrequently epi- 
thelial cells are thrown 
off, with a single large 
fat globule in the body 
of the cell, known as 
' ' seal-ring cells. ' ' In 
such cases the fat glob- 
ules have a ''moon" or 
''cap" appearance. 

4. Leucocytes of all 
forms are frequently met 
with in milk such as 
mononuclear basophiles, 
eosinophiles, polynuclear 
basophiles, acidophiles, 
or cells with neutrophilic 
and eosinophilic granules 
in the protoplasm. 

If the polynuclear 
cells show no nuclear 
bridges, they may be 
found with % or more 
spherical shaped nuclear 
granules ( spherical gran- 
ule polynuclear leuco- 
cytes, Babs.) The nu- 
cleus is usually in the 
shape of a ribbon, or clover leaf, or heartshaped. The protoplasm 
usually contams fat globules, which in stained preparations appear 
as fine vacuoles. 

The lymphocytes are small cells with round nuclei and a verv 
small border of protoplasm. According to Schulz they never con- 
tain fat. Large mononuclear leucocytes are also supposed to be 
present m the milk. If they gorge themselves with fat thev are 
filled to their fullest extent, and can no longer be distinguished 
from fat-containing epithelial cells. 

5. The red blood cells may be seen as small, round or thorn- 




Sediment in milk of a cow after milk stasis. Numer- 
ous desquamated epithelia, among these an "albu- 
mmophore," and polynuclear leucocytes. 



28 



Microscopy of Milk in General. 



apple shaped bodies, witli metachromatic staining substances. 
They may be readilj'^ recognized as erythrocytes. 

6. Degeneration of these various kinds of cells may result in 
the finding of the most peculiar formations. 

The protoplasm of the epithelial cells becomes shredded ; the 
nucleus splits up and eliminates its chromatin into the plasma in 
the form of dust or flakes. It diffusely passes into the cell pro- 
toplasm, which appears darkly stained, and in the place of the 

Fiff. 13. 

















^Mf 



The formation of large colostral spheres and desquamation of "seal-ring cells." 

1 X 800. 

nucleus a pale vacuole appears. If the breaking down continues 
there may appear a disintegration of the cell and of its nucleus into 
small droplets and fragments of roundish appearance, either with 
or without a lightly stained border around a small darkly stained 
center of chromatin (Heidenheim, Colm, Popper, Schulz). These 
chromatin flakes are probably identical with the so-called free 
nuclei (Michaelis), which were also observed by Lenfers. 

The flakes which result from chromatolysis have been des- 



Cellular Content of Milk. 



29 



Fisr. 14. 



ignated up to the present as "Nissen's Globules." According to 
Ottolenghi they are derived either from leucocytes or from 
epithelia. 

If fat-containing cells break down in this manner, fat globules 
in the shape of grape-like bunches, and single fat globules result, 
which are united by a mesh of fine protoplasm, or they are sur- 
rounded in the form of a moon by a narrow border of protoplasm, 
which crowded to one side rests like a cap on the fat globules. 
Such moon and cap formations may also result in another way. 
The leucocytes (mac- 
rocytes), crowd on to 
the dead or dying cells, 
eat their way into the 
cell bodies and establish 
in the more and more 
distending cell actual 
lacunas, in which the de- 
vouring leucocytes lie. 
The remains of the pro- 
toplasm and of the cell 
and nuclear membranes 
float in the shape of 
caps and moons in the 
milk protoplasm until 
the swelling or further 
breaking down converts 
them into spheres or 
globules. At the same 
time of course the mac- 
rocytes may t h e m - 
selves degenerate in the 
cell, and no longer pre- 
sent a recognizable nu- 
cleus. In such cases its 
respective lacuna con- 
tains homogeneous, 
sharply circumscribed 
proteid globules. 

The author consi(]ers these epithelial cells which have been destroyed by macro- 
phages, as identical with the albuminophores of Bab and Schulz which "they described 
as large lymphocytes, (15 to 20/x), containing fat and 1 to 4 or more proteid globules. 

_ Besides these regularly formed constituents of the milk, its 
sediment contains flaky constituents, small irregular shaped coag- 
ula, which readily tinge with basic anilin dyes, or with nuclear 
staining substances. Frequently they are without any structure. 
At times they appear in individual milkings, almost completely 
dominating the microscopical field. They are the early stages of 
the corpora amylacea, soon to be descrilied, which apjpear either 




Budding globules, free nuclei, Nissen's globules, that is 

cell fragments, in the sediment of cow's milk, 

1 X 1000. 



30 



Microscopy of Milk in General. 



roiiiul, oval, bean-shaped, or nodular, ranging from very small 
(1 to 2 /Lt), to an enormous size (5 to 200 m according to Zimmer- 
mann). These bodies show no concentric formation, or radial 
stripes. They usually appear during abnormal activity of the 
gland, and are found in colostrum, in stasis of the milk, in mastitis, 
in the inactive glands of older animals, etc. Their varied thickness 
makes active turning of the micrometer screw necessary. 

These corpora amiilocca (according to Siegert, corp. flava in contra-distinetion 
from Corp. versicolorata, are tlie ^anie as aniylacea) were seen by Herz, Ottolen>fhi, 
Iwanoff, and later described by Martin, Lenfers, Winkler and Zimmermann. Wederhake 



Vvj. 15. 




Epithelia in different stages of destruction by macrocytes, tliat is so-called 
albuminophores. 1 X 1000. 

confirmed their occ-nrrence in the colostrum of women, and compared them with the corp. 
amylacea of the prostate gland. 

A section offers the best opportunity for the microscopical 
study of the nature of these bodies. In preparations of acute 
mastitis, their development is especially clear. Around small 
flakes of proteids, possibly precipitated nuclear or cell fragments, 
layer after layer will be formed until a concrement results, which 
may even fill the entire alveolus. Lime and salts of magnesium are 
later absorbed by this basic structure of concentric layers, and fine 



Milk Concreinents. 



31 



radiated stripes appear upon its surface in consequence (Fig. 13, 
Fig. 16 and Table I.). 

While the alveolar epithelium succumbs to the pressure of the growing eoncrement, 
and may be absorbed for some time, the eoncrement resists the influences of the organs, 
and finally is surrounded by connective tissue. Zimmermann states that the bodies may 
be either in the alveolus or on or under the epithelial layer, and even free in the con- 
nective tissue. These observations have been confirmed by the author. 

Tliey stain with metlijdene blue, iodine green, and gentian 
violet, similar to otlier amyloid substances, but do not give the 
starch reaction with 

iodine solution and sul- Fig. 16. 

phuric acid (Zimmer- 
mann, and author's ob- 
servations ) . Wederhake 
and Winkler claim to 
have obtained a bluish 
violet coloration with 
iodine. 

The corpora amy- 
lacea of the mammary 
glands resist few acids 
(sulphuric acid, hydro- 
chloric acid). Otto- 
lenghi and Zimmermann 
obtained a solution with 
pure sulphuric acid. 

They are therefore 
pure concrements of se- 
cretion which form un- 
der peculiar conditions. 
Their quality varies, 
depending on the char- 
acter of the precipita- 
tions, which combine to 

lOrm tnem. Lime eoncrement in the milk sediment of a cow. 

1 X 1000. 

What remarkable significance may be attached to such conditions may be indicated 
by the views of Herz, who considers them as the initial formation of casein, and those 
by Winkler, who believes that they change into fat or that they are degenerated 
epithelium. 

Leucocytes also crowd upon these bodies, and attempt to dis- 
solve them just as osteoclasts attack bones. Under their influence, 
combined with that of the body juices, a destruction, solution and 
absorption of the concrements may take place, or on the other hand 
new layers of thickened secretion may form around the old debris, 
and a new eoncrement develops. 

This describes, with the exception of the fat globules, the cell 
elements which may be demonstrated under the microscope, as far 
as they originate from the udder of the cow. The fat globules will 
be discussed under the heading of milk fat. 




Chapter IV. 

COMPOSITION OF MILK AND ITS BIOLOGICAL, CHEMICAL 
AND PHYSICAL CHARACTERISTICS. 

There is very little known with absolute certainty relative to 
the development of the individual constituents of milk. The 
theories in this regard are almost entirely hypothetical. It is 
certain that milk constitutes the specific product of cell activity of 
the glandular parenchyma, and does not represent a simple trans- 
udation of the constituents of blood, with a mixture of broken down 
products of cells (nuclear masses of leucocytes and epithelia, and 
fatty detritus), nor the fatty breaking down of the epithelium 
(Reinhardt, Virchow, Skanzoni, Koelliker), nor partial epithelial 
degeneration of the parts lying adjacent to the lumen (Heiden- 
hain), nor transformation of leucocytes and lymph cells (Rauber). 
None of these is the basic pheonomenon in the formation of milk, 
but it is due instead to the assimilating activity of the cells, which 
send their secretion into the lumen of the cell tube (Ottolenghi). 
A breaking down of cells of course occurs to a greater or lesser 
extent, in accordance with their increased activity, and therefore 
the milk contains cells and cell fragments in varied quantities, 
without this throwing off of cells or breaking down of cells having 
anything to do directly with the secretion proper. The throwing 
off of useless material, and its natural replacement by functionat- 
ing elements are only signs that the organ desires to maintain itself 
in a condition capable of continued secretion. 

Our attention has previously been directed principally to the 
functions and activities of the milk gland from a physiological point 
of view; the morphological condition of the udder and some con- 
stituents of the secretion have also been noted. In this chapter the 
chemical qualities of the milk will be considered, as far as this is 
necessary for the most ordinary conception of these properties. 

The quality of the milk — in the liroadest sense — adjusts itself 
to the requirements of the young. The milk gland offers it nutri- 
tive and protective material in a form which most favorably meets 
the requirements of the off-spring. 

In orcler to give only a few examples attention should he direfted to the estah- 
lished facts, which show that there exist ahsohite relations between the time required 

32 



ComiDosition of Milk. 



for the doubling of the weight of the young and the percentage of proteids in the milk; 
between the proportion of certain salts and the ash constituent, and the rapid growth of 
the young; between the growth of the brain and the supply of proteids and lecithin. 

Milk consists of dissolved constituents, and this solution con- 
tains substances in suspension ; in the entire mixture there are also 
undissolved substances in emulsion. 

The dissolved and suspended substances are designated as 
milk plasma, which after coagulation separates in milk serum and 
coagulum. The fat is present in an emulsion; there are in addi- 
tion to this several salts, coagulums, cells, etc., undissolved or in 
a precipitated condition. In coagulation the casein which at first is 
in suspension, thickens, and carries down the undissolved sub- 
stances, separating more or less from the milk serum in which the 
soluble salts, milk sugar, certain proteids, ferments, coloring mat- 
ter, etc., remain. 

The principal constituents of the milk, which constitute as well 
the principal properties of the glandular secretions, are the parts 
which have received the most thorough study. 

The proteids. Casein, milk albumen, and milk globulin (traces 
of lactomucins, and possibly traces of other proteid substances, 
which remain after acid precipitation and boiling, being known 
collectively as lactoproteins) are the protein constituents of milk. 

The fat; the milk sugar. The milk further contains lecithin, 
sarcin, kreatinin, nuclein, urea and sulphocyanic acid. 

Nothing is known at the present time of some of these constit- 
uents, whether they occur originally in the milk, or whether they 
are only split products, which result during the final production of 
the various principal constituents, or through bacterial action in 
the milk; of such substances may be mentioned peptone, ammonia, 
leucin, etc. 

Of non-nitrogenous substances milk also contains citric acid, 
cholesterin and under certain conditions free lactic acid, alcohol 
and acetic acid. 

_ Gases which occur free in milk are oxygen, nitrogen, and oc- 
casionally carbonic acid ; the salts are combinations of the bases of 
sodium, potassium, magnesium, calcium, and iron, with hydro- 
chloric acid, sulphuric acid, phosphoric acid, carbonic acid, and 
citric acid. 

Principal Constituents. 

Casein is a proteid especially characteristic of milk, occur- 
ring almost exclusively in the milk gland secretion of mammalia, in 
quantities of from 2 to 4 per cent. 

(It is supposed to occur also in the secretion of the sebaceous 
glands of mammaha and in the coccygeal gland of birds.) 

The origin of casein is unknown. It was formerly supposed that it originated from 

an enzymic change of serum albumen produced by the action of enzyme-like bodies 

upon the albumen. However, since it has been found that the assertion of Kemmerich, 

relative to the increase of the casein at the expense of the laetalbumen, after the di- 

3 



34 Bioloiiical, Cliemieal and Physical Characteristics of Milk. 

gestion of milk at lilood temperature for several hours was incorrect (Schmidt and Tier- 
fehloi', likewise that casein is not produced by mixing hlood serum and nuicerated milk 
gland structure, or milk gland juice and ovalbumin, and es[)ecially since it is known that 
casein rej)rcsents a luiclear albumin containing phosphorus, the euzymic origin of the 
casein in the above sense is denied. For a time Basch 's hypothesis relative to the origin 
of the casein was accepted, namely that the nucleic acid which is set free in the alveoli 
by the activity of the gland, combines with the transuded blood serum, forming the 
nucleo-albuniin, the "casein." Investigation of the experiments of Basch by Odenius, 
Mendel, Levene and Lobisch proved however that Basch 's hypothesis cannot stand. 

At the present time it must be admitted that the cells of the 
milk g-laiid break up the proteids into more simple bodies, and then 
bnild up the casein from these products. 

The casein is distinguished from other proteids containing phosphorus, as for in- 
stance from the nucleo-proteids, l>y the absence of the xanthin group, the pyrimidins, 
and the pentose group. The consistence of casein from various species of animals varies 
chemically to a considerable extent. By special reactions with casein anti-serum 
(precipitation, complement fixation), the caseins from different species of animals may 
be differentiated one from the other. Tn the splitting up of casein into its various con- 
stituents, quantitative differences in these split products are found which indicate the 
differences in the individual caseins. 

The cow casein contains 
according to C. 

Tano-1 52.99 

Ellenberger .... 53.07 

Burow 52.825 

Hammarsten ... 52.96 

It is insoluble in water and in alcohol, but with bases forms 
solutions, the so-called caseinates. Alkali-caseinates form opales- 
cent solutions, while solutions from caseinates of earthy alkalies 
represent cloudy, milky fluids. Casein is slightly acid, the solution 
of which with the bases is accompanied by the formation of salt-like 
compounds. 

The characteristics of casein are of especial interest, as they 
give to the milk its well known properties of rennet-coagulation, 
and easy acid coagulation, etc. 

Casein is present in the milk as caseinate of lime, in suspended 
condition as dicalcium-caseinate, which gives an acid reaction to 
phenolphthalein, and a neutral reaction to litmus. 

Acid abstracts calcium from the caseinate, the casein being 
precipitated (that is casein from the milk of cows and other rum- 
inants) as coarse, flaky material, while the casein from the milk of 
solipeds and women is precipitated as a fine, flaky substance. 

This difference in its properties is traceable to the physical condition which is mani- 
fested by the casein molecule of the various kinds of milk (Fuld and Wohlgemut) ; but 
it may also be the result of a variation in the quantity of salt and proteid present in the 
milk. 

In the presence of di- and tri-phosphates the casein dissolves 
by combining with a part of the bases, so that the neutral and alka- 
line phosphates change into monophosphates (Hammarsten^ 
Arthus). 



H. 


S. P. 


N. 


0. 


6.81 


0.832 0.877 


15.65 


23.141% 


7.13 


0.76 0.80 


15.64 


22.60 % 


7.095 


0.725 0.808 


15.64 


22.906fo 


7.05 


0.758 0.847 


15.65 





Casein. 35 

Casein is also soluble in other salts, but not, or only to a very 
slight extent in NaCl, Naa SO4, NaNOs, KCl and others. 

In the presence of an excess of acid the casein which is first 
precipitated is again dissolved into a syrup-like mass, but may be 
again recovered as casein after neutralization. Neutral calcium 
casein suspensions do not coagulate in boiling, but they form a 
pellicle on the surface. (The nature of this manifestation is not 
entirely clear, but depends probably on the drying and transforma- 
tion of the casein into a more solid form.) 

Casein is precipitated even in the presence of relatively small 
quantities of acid while boiling under this condition changes it 
slowly into a body not susceptible to the action of rennet. In over- 
heating and likewise in boiling and over-heating with small excesses 
of alkali, casein is split up through hydrolysis. 

Even under the action of water, casein is split up into a pro- 
teid body which is coagulated by heat, passes through a filter and 
is probably identical with whey casein. 

The latter substance is formed after the precipitation of the 
cheesy substance, through the action of rennet, and is a mixture of 
reduction products of the casein originating through the action of 
the rennet (Raudnitz). 

One characteristic property of casein is its precipitation by 
rennet in the presence of earthy alkali salts. The precipitation of 
casein has no connection with the action of the rennet as such. This 
may occur even without having precipitation as a result. If for 
instance a casein solution is mixed with active rennet, and another 
solution mixed with inactive boiled rennet, then in the mixture con- 
taining active rennet, para-casein is formed without any action 
being noticeable. Only after the addition of soluble calcium salts 
will precipitation of the para-casein calcium result in the glass 
which contains the active rennet, but not in the glass containing 
rennet which has been inactivated by heating. 

In the change of casein by the rennet ferment, there results in addition to the 
substance designated as para-casein, another proteid body free of phosphorus, with the 
properties of albumose, the whey-proteid (Hammarsten). 

The change of the casein to para-casein, and whey proteid may 
be a splitting up of the casein, or it may depend on a change in 
the grouping of the molecules, or it may correspond to a change in 
its physical condition. 

The action of rennet in the curdling of milk is practically the 
same as in casein solutions ; however it is influenced by the other 
(dissolved) substances, by the other proteids and salts, and pos- 
sibly also by the physical condition of the fatty emulsion. 

Curdling with calf rennet develops in accordance with definite 
laws. In milk that has been brought to low temperatures (refrigera- 
tor) the action of the rennet may be established by subsequent heat- 
ing; the precipitation, however, will not take place until the mix- 
ture is heated to 37 deg. C. (Morgenroth.) 



3(3 Bioloyical, Clioinic-al and Physical Characteristics of Milk. 

Coagulation may not always appear if the milk is immediately heated to .TT (leg., 
which would indicate that some of the rennet is destroyed at 37 lieg. 

If the same milk is utilized under the same experimental con- 
ditions, it can be seen that the amount of rennet necessary for the 
coagulation of the milk is nearly proportionately opposite to tlie 
leng'th of time necessary for the coagulation to ])e completed; this 
fact is expressed by Storch and Segeike as follows : "The product 
from the quantity of ferment and time of coagulation is constant." 

Each kind of rennet has a certain strength which of course is changeable, and rela- 
tive for each sample of milk. In strong dilutions of the rennet the action does not corre- 
spond with the time rule, the time of coagulation becoming continually longer UJito 
intinityj that is, coagulation finally no longer takes place. 

The action of rennet depends on the most varied factors, 
which may either hasten or retard its action and influence the 
l)recipitation. 

Acids for instance strengthen the rennet action, likewise 
earthy alkali salts, while alkalies, albumoses, neutral salts of high- 
er concentrations, heating of the milk, talcum, caolin, and muci- 
laginous substances retard the rennet action. Shaking reduces the 
strength of the rennet if it is in solution. 

The following data are taken from a work of Smeliansky in order to show the in- 
fluence of various additions on the rennet coagulation of cow's milk. 
It appears that: 

1. Heating the milk results in retarding the action. The longer the heating lasts 
the softer and smaller are the flakes. 

2. Addition of water likewise retards the action. 

3. Mucilaginous substances retard the rennet action from taking place, and the 
flakes formed aie soft and loose. Barley water esi)ecially influences its consistence while 
corn water principally alters the time of coagulation. 

If boiled milk is diluted with equal parts of a mucilaginous infusion and water, the 
mucilaginous portions coagulate more quickly than the watery parts. 

4. The addition of soda solution renders the flakes soft, and retards coagulation. 
Milk containing 0.5% of soda is entirely prevented from coagulating even after standing 
for 24 hours. 

Four per cent of table salt renders the flakes softer. Potassium carbonate acts 
the same as soda while the other salts respond according to their alkalinity. 

5. Milk of lime retards the action ; chlorate of lime accelerates it. If boiled milk 
for instance coagulates after 6% hours, the time required for coagulation after the addi- 
tion of Ca Clo is only S to 15 minutes. It causes the flakes of raw milk to become loose 
and soft. 

According to Smeliansky, the reaction indicates the character of the coagulation, 
and the time required for it. Sugars exert no influence. 

On the other hand Reichel-Spiro have determined a slight retarding of coagulation 
in the presence of a high content of cane sugar. 

Cooking the milk retards the process (lowering the acidity as 
a result of "the loss of COo and precipitation of lime salts, Eaud- 
nitz). In overheated milk no coagulation or only poor coagulation 
takes place. The addition of water retards coagulation (Weitzel), 
likewise physiological salt solution or whey which is free of ren- 
net (Reichel-Spiro). Hammarsten, Lorcher, Peters, Weitzel, 
Gerber and Eaudnitz conducted experiments relative to the action 
of salts on coagulation, the results of which according to Raudnitz 
may be interpreted as follows : 



Rennet. 37 

1. The cliemical reaction of rennet is hastened by the distri- 
bution of the rennet and its quantitative relation to the casein, pos- 
sibly also by elevated temperatures up to an unknown limit. Alka- 
line earths and acids probably act in a similar manner by activat- 
ing the rennet. 

2. The chemical reaction is retarded : (a) By the destruction 
of the rennet : temperatures over 41° C, free hydroxylions ; (b) by 
inactivation of the same: anti-rennet; _(c) by changes of the 
casein : temperatures over 80 deg. ; formalin. 

3. The physical reaction is hastened by higher temperatures, 
free Iwdrogenions, and the neutral salts up to a certain concentra- 
tion, especially the salts of alkaline earths. 

4. The physical reaction is retarded by reducing the concen- 
tration of the mentioned salts below a certain point, especially^ of 
the alkaline earths ; therefore heating the milk and the salts which 
precipitate lime, and calciumions will produce this result. Higher 
concentrations of neutral salts have the same effect. It may also be 
possible that some of the alkaline action should be considered here. 

It is known that by the injection of rennet into an animal an 
anti-rennet may be produced. The rennet acting as antigen 
induces in the body of the rabbit the formation of a specifically 
acting anti-body, which works against the action of the antigen in 
the re-agent glass, very likely through fixation. Normal serum 
also contains rennet-inhibiting substances. 

The action of the rennet may be inhibited or entirely prevented by the addition of 
horse blood as has been proved by Hammarsten, and later by Eoden. The same inhibi- 
tion is exerted on the action of trypsin and pepsin and is referred to as an anti-ferment 
action of the blood sernm. Blood of cattle added to cow's milk also shows this chai- 
acteristic (Schern). Inhibition action is traced back to the anti-ferment substances of 
a specific nature contained in the blood, and the presence of an anti-rennet is considered 
probable. It should however be noted that Eaudnitz and Jakoby prevented inhibition 
by neutralizing the serum with acid. 

The strength of the rennet may be tested in various ways. 
That quantity of milk is measured which is coagulated by one part 
of rennet in 40 minutes at 35 deg. Market rennet has a strength 
of 1:10,000 to 1:100,000 (fluid rennet and solid rennet). 

Meunier ascertains the quantity of milk which is coagulated by one e. c. of undi- 
luted gastric juice in ten minutes. Schern employs solutions of rennet (standard rennet 
prepared according to Morgenroth) of varying density (1:100:200:300, etc). One part 
of these rennet dilutions is mixed with nine parts of milk, so that milk-rennet dilutions 
of 1:10D0: 2000: 3000, etc. are obtained. After an action of two hours the samples are 
placed in the incubator. The dilutions in which coagulation may now be demonstrated 
give the relative value of the rennet for the respective milk, and if a mixed milk of 
healthy animals had been used it establishes the " rennet-titer. " 

it is to be regretted that the standard rennet solutions are not 
constant, and that they weaken by storing, etc. For this reason it 
is necessary to establish the rennet-titer before each test on the milk 
of healthy animals, or on casein solutions. 

In addition to the rennet of calves, extracts and ferments from other organs of these 
animals act on milk in a similar manner, such as extracts of spleen, kidney, liver, lung, 
thymus, intestine, ovaries, testicles and muscles. Eennet from the stomach of a calf is 
known as chymosin; rennet from the stomach of a hog, and from the gastric juice of man 
as parachymosin (Bang). Eennet enzymes may also be demonstrated in the bodies of 
other animals, fish, birds and snails. 



38 Biological, Chemical and Physical Characteristics of Milk. 

Enzymes 'vvith the action of rennet have been found in various plants and parts 
of plants, such as tlie artichoke, branches of fifj trees, candytuft (Iberis ])innata), 
yellow mustard (Jsatis tinctoria), etc., also in bacteria (}>roteolytic) and in yeast. 

The indiviilual kinds of rennets vary considerably in their sensitiveness to various 
influences. 

Whereas the rennet of calves is very susceptible to heat, and exerts its action 
readily in alkaline solutions, the parachymosin is less influenced liy the harmful action 
of heat, but is jirreatly affected in its action by the presence of alkalies. 

The rennet enzyines obtained from plants act in an optimal way at high tem- 
peratures (sykochymas at 65-70 deg. C. for raw, at 85 deg. C. for sterilized milk). 

Aside from casein, milk contains proteids which are coagTilable 
by heat. 

(1) Lactalbumin which is related to the sermii albmnin but is 
not identical with it (it has a slight optical polarization: — 36.4 to 
— 38 against — CO.l to — 62.6, Sebelien). 

(2) Lacto-globulin may be precipitated with the aid of mag- 
nesimii sulphate. It is contained in milk in quantities of about . 1 
per cent, of the total proteids. The lacto-albumin is obtained from 
the residual solution after saturation with magnesium sulphate and 
acidifying it, or by almost complete saturation with ammonium sul- 
phate. 

3. Lacto-mucin has been also demonstrated in milk by Storch, Siegfeld, Yoltz 
and Eosengren, whereas other proteid substances such as albumose, peptone, albuminose, 
lacto-protein, gelatin, galaetozymase and opalisin, are considered more recently as 
pro<1ucts of the preparation of other proteid bodies, at least so far as their appearance 
in ripe milk is concerned. 

The proteids which remain in the fluid after precipitation with 
acid and boiling are collected under the term "lacto-protein." 

The milk fat consists of a mixture of triglycerides, clioles- 
terin, lecithin, and a coloring substance, and distinguishes itself 
considerably from the fat of the body and from the nutritive fat 
by its chemical and physical characteristics. Although the milk 
fats manifest considerable dependence upon the nutritive fat, as 
will be seen from the later chapters, nevertheless a transition of 
the nutritive fat into milk fat cannot be asserted. The same state- 
ment would also apply to the transition of body fat, although in 
this instance a closer relationship between the substances must be 
admitted. 

It is possible that transitory relations exist, by means of which split up body 
fat may be converted in the milk gland into milk fat, and thus the nutritive fat 
takes ])art indirectly in the formation of milk fat after first having been deposited 
as body fat. 

It should be considered however, that the specific activity of the cell builds up 
the fat from the constituents at hand, and utilizes whatever material is placed at its 
disposition, such as nutritive fat, when such is present, or body fat in emergencies. 
The ])roduct will approach in its properties the material which has been utilized, but 
will always remain peculiar to the species of animal producing it. 

A formation of fat from proteid is possible, as may be seen 
when cows are fed with substances free of fat, and after the body 
fat deposits have been used up. It is probable that the carbohy- 
drates of the food here take part in the formation of fat. 



Fat Content. 39 



The fat which is contained in milk in the form of very fine 
globules, causes in part the white color of the milk through the 
reflection of light. The size of the fat globules varies in the milk of 
the same cow and depends upon the individual, length of the period 
of lactation, the race, feeding, and upon whether the first, middle 
or the last part of the milking is examined. According to Woll, 
D'Hunt, Schellenberger and Gutzeit the diameter varies between 
0.8 and 22 /. with an average of 2.2:2.5:2.9:3.6 /^. 

Variations in the percentage of fat are caused by change of 
food, etc. These changes also have an influence on the size of the fat 
globules, and according to Woll the fat globules become larger with 
dry feeding, a statement which could not however be confirmed 
by Schellenberger and Pankowsky. According to the investigations 
of these authors the feeding of green forage, especially clover, 
produces large-sized fat globules. 

The length of the period of lactation should be considered since 
the variations of size at the beginning of lactation are more con- 
siderable than in ripe milk, in which the milk globules appear more 
uniform and mostly of medium size. 

In colostrum they vary from the sizes of dnst to 20/^ and over. Donne and 
Schulz found that colostrum contains large, broad oil drops in addition to the small 
and minute fat globules, which show a less uniform appearance and contour, when 
compared with the usually spherical fat globules of ripe milk. 

In interrupted milking the size of the milk globules bears a 
certain relation to the fat content. With the increased quantity 
of fat which obtain in the milk toward the end of a single milking, 
the size of the fat globules also become larger (Schellenberger, 
Woll). 

With the extension of the lactation period the size of the fat 
globules decreases, but their number increases. 

According to Gutzeit and Schellenberger the following values were obtained in 
milk from different breeds: 

Size in 1/1000 mm. No. per ec. in millions. 
Gutzeit : Schellenberger : 

Voigtlander 2.73 1944 to 4476.9 

Jersey 3.5 2.95 2064.1 to 4643.3 

East Friesian 2.30 2521.0 to 5911.0 

Angus' 2.95 2.20 2886.0 to 6200.0 

Simmenthal 2.56 2995.0 to 5210.3 

Dessau 3070.0 to 6308.6 

Swiss 2.33 4008.0 to 5326.7 

Shorthorn 2.76 

Montavoner 2.62 

Ilolstein 2.58 

Breitenburger 2.46 

According to Grimmer the number of milk globules fluctuated in 21 tests on 
three herds of blackish-brown lowland cattle in Pomerania, from 1,330,000 to 3,073,000 
per cubic millimeter, having an average diameter of 2.6-3.7/^. 

The milk globules retain their form through their surface 
tension and are not surrounded by special capsules which could be 
considered as membranes, as has been thought by former authors. 



40 Biological, Chemical and Physical Characteristics of Milk. 



Although the milk globules eaunot bo outiroly fiood from jnoteiils l»y washing 
(eovering the luilk with water and allowing the ^^epaiatioii of fat), the ileuioustration 
of the remains of juoteiiis cannot be considered as proof of an actual "haptogen ukmu- 
brane " which must be broken down during the butter-making process, in order to make 
possible the flowing together of the milk fat, but it does constitute a proof that rem- 
nants of proteids, even after the most careful washing of the cream, remain around 
the fat globules. At least it has never been jiossible to demonstrate membranes of the 
fat globules, neither in boiled milk, in which during continuous heating larger fat 
cdumps develop, nor in fat extractions (Soxhlet, Quincke, Alorres). 

Milk sugar is also a specific substance of milk. It is formed 
in the i>iancl and is found only in its secretion. If sucking is in- 
terrnpted, it may be present in the urine, from which it immedi- 
ately disappears upon amputation of the lactating gland, or it may 
not appear at all when the gland is amputated l)efore the appear- 
ance of lactation (Sinet, Magnns-Levy, Znntz). After the com- 
plete removal of the gland in goats and cows, however, a temporary 
hyperglycosemia and glycosuria appear. If parts of the gland 
remain, lactosuria results. 

After the injection of glucose, lactose appears in the nrine 
(Porcher), likewise after the ingestion of large quantities of dex- 
trose. Since the blood in the mammary vein before parturition 
and during lactation contains considerably less glucose than 
the blood of the jugular vein (Kaufman and Lagne), it may be 
accepted that glucose has been utilized in the gland, and further 
that glucose is the material from the constituents of which the lac- 
tose is formed in the gland. 

Of the various salts milk contains compounds of potassium, 
calcium, magnesium, iron, traces of manganese, aluminum, phos- 
phoric acid, hydrochloric acid, carbonic acid, sulphuric acid, citric 
acid, fluorine and iodine. 

Carbonic acid, oxygen and nitrogen have been demonstrated as 
gases in the milk. 

Besides these substances, lecithin, cholesterine and coloring 
matter are present in the milk, besides ferments and substances 
which are collected as residual substances; these have been pre- 
viously mentioned. 

Eaudnitz and Grimmer have recently published compiled arti- 
cles relative to the individual constituents and chemical properties 
of milk which contain the collected material of many experimental 
results, and at the same time show how much is still unsettled in 
regard to the composition of milk and the characteristics of the 
substances which it contains. 

Certain physical characteristics of milk correspond to its 
chemical condition. These adjust themselves according to the pro- 
portion of the various constituents, and to the conditions attend- 
ing the mixing of the different component parts. 

The appearance of the milk is influenced by the suspended 
casein and the proportion of fat. Skimmed milk, Avhich is almost 
free from fat constitutes a non-transparent, somewhat bluish fluid, 
as compared with the whitish yellow color of whole milk. The ad- 



Specific Gravity of Milk. 41 



dition of alkalies to milk free of fat renders it transparent. Ham- 
marsten furnished the proof that a calcium caseinate solution which 
corresponds to the composition of milk is almost as non-trans- 
parent as milk. The milk becomes less transparent the smaller the 
fat globules are. This is most strikingly apparent when the fat 
globules are broken up to dust-sized bodies (for instance through 
homogenization). The appearance of fresh milk is also influenced 
by the coloring matter present in the milk plasma and in the fat. 
It is known that the skimmed milk of certain cows varies considera- 
bly in color; at times it is bluish white, sometimes more yellowish 
green, again transparent, other times of a non-transparent whitish 
color, and also the fat has a more yellow color during the pasturing 
of the animals than at the time of stable feeding. 

The non-transpareney as mentioned above is no proof of the presence of fat in 
the milk; therefore all methods which are destined to establish the quantity of fat or 
addition of water by the establishment of the whiteness, are of no use, as for instance, 
Heeren 's pioscope, Feser 's lactoscope, etc. 

Tf milk is allowed to stand for a time, cream forms on the 
surface ; the fat globules rise and collect usually as a distinct layer 
of cream above the milk. The rapidity of the separation depends 
on the temperature, the size of the fat globules, and the density of 
the milk plasma. The quantity of the cream is not in parallel rela- 
tion to the quantity of fat ; it depends on the size of the fat globules. 

The separation of cream may be hastened and increased by 
centrifugalization. During separation while allowing to stand, 
about 85% of the fat rises to the surface, while by a perfectly 
operating centrifuge the separation of cream may be accomplished 
up to 0.01% of its M. 

The specific gravity of the milk depends on the solid sub- 
stances, the relation of the mixture and the condition of the sus- 
pended, dissolved, and emulsified constituents of the solid siib- 
stances. Corresponding to the variable composition of cow's milk 
it is natural that the specific gravity of the milk should vary. 
It fluctuates considerably, varying from 1.027 to 1.034 at a 
temperature of 15 deg. Similar to the impossibility of speaking of 
milk of normal composition, one cannot speak of milk of normal 
specific gravity, and even to give average figures would be of very 
problematical value; but to take such average figures or even 
smallest values as a iDasis for the calculation of falsification would 
be a gross error. Milk from many cows would under ordinary con- 
ditions have a specific gravity of 1,029 to 1,033. 

The specific gravity is measured, or is calculated from the 
values of fat contents and solids, according to formulas, which, 
depending on the milk from certain breeds, or certain localities, 
show slight variations. This formula made on the basis of the 
value of the specific gravity of the milk fat (about 0.93), and the 
solids or dry substances (1.6001), which is quite constant, is 
according to Fleischmann: 



42 Biological, Chemical and Physical Characteristics of Milk. 



1000 



1000—3.75 (d— 1.2f) 

In these equations s stands for specilic gravity, d for dry 
substances or solids, and f for fat. 

The following- vahies may also be calculated from the fat con- 
tents of the milk and its si^ecilic gravity. 

1. Total solids : 

d=1.2f+2.665X™^=^^ 

s 

2. The fat-free solids are shown by deducing the percentage 
of fat from the percentage of the total "solids. 

3. The specific gravity of the solids 

_ ' sXd 

~ sXd— (100 s— 100) 

4. Finally the fat contents when the solids and specific grav- 
ity are known : 

f=0. 833 (1-2.22^2=122 

S 

The values obtained from formulas are of course not abso- 
lutely correct, but represent the results only approximately with 
the analytical methods of weights, the fat-free dry substance of the 
milk is not of absolute constant composition, but varies, so that its 
specific gravity which is based upon the sugars, proteids and salts, 
varies more or less from the number which has been accepted by 
Fleisehmann as the average value (1 . 60). 

The equations hold only for cow's milk. 

If milk is freshly drawn, and immediately tested it shows a 
considerably lower specific gravity (0.0008-6.0015), than after 
cooling. The milk ''contracts" and becomes constant in its specific 
gravity only after standing for several hours. The cause of this 
manifestation is not yet entirely clear. Toyonaga aims to explain 
it by the fixing of previously uncooled and fluid fat globules, which 
is the most plausible explanation ; other authors believe that the 
contraction is the result of a cessation of the expansion of the 
casein. 

The density of the milk varies in accordance with the tempera- 
ture. The maximum (for water at 4 deg.) lies almost near its 
freezing point, namely at . 3 deg. C. 

The freezing point of milk is somewhat lower, namely — . 54 
to — 0. 57 deg. This is especially influenced by the presence of salt, 
less by the sugar contents of the individual samples of milk, and 
it is induced by the relatively constant amount of soluble salts 
in the salt contents, which is subject to only slight fluctuations in 
the milk of healthy animals. 

For the sake of completeness the electrical conductibiiity of 
the milk should also be mentioned. This varies according to the re- 
sistance which is offered by the fluid to the current. It fluctuates 



Polarization of Milk. 43 



within wider borders than the freezing point, and is influenced ac- 
cording to Zanger by general diseases, through local affections of 
the udder, by estrum, pregnancy, feeding, etc. The conductivity is 
diminished by the fat globules ; therefore skim milk conducts better 
than whole milk or cream. The conductivity of the different quar- 
ters is inversely proportional to the quantity of milk, in milk from 
different quarters of one cow (Schnorf). 

The viscosity of milk is a factor which principally depends 
on the condition and on the quantity of the casein and the fat. 
Higher temperatures reduce the viscosity, likewise shaking ; quiet 
standing increases it. 

The surface tension of milk is lower than that of water 
(0.053 against 0.075). 

Of the physical properties the specific gravity of milk and its 
serum, and the polarization of milk serum, are of special impor- 
tance for the practical testing of milk (see technique). For practi- 
cal results, however, the determination of the fat contents is also 
necessary. 

As it has been shown the total solids may be determined by 
the aid of the fat contents and the specific gravity and the fat-free 
solids may be established by deducting the percentage of fat, 
these four factors are generally sufficient for the preliminary 
tests. For more accurate study these preliminary tests are com- 
pleted by the establishment of the specific gravity of the milk 
serum, or still better by the ref ractoscope to determine the chlorids 
of calcium serum, which renders more rapid work possible. This 
is a method whose satisfactory use in practice has been proven by 
the numerous works of Mai and Eothenfusser. 

Publications relative to the polarization of milk were issued 
by Valentin in 1879, and later continued by Villiers and Bertault, 
Braun, Utz, Lam, Radulesku, Ripper, Schnorf and others, on ren- 
net serum, acetic acid serum and milk serum, which had been pre- 
pared by voluntary coagulation. 

The given values of the authors varied in accordance with the 
method of preparation of the serum; nevertheless it could be estab- 
lished that comparatively uniform figures were obtained whenever 
the work was carried out under similar experimental conditions. 
In 1908 Cornalba showed that contrary to the variance in the 
amount of colloidal substances dissolved or suspended in milk, the 
sum of the dissolved constituents of milk is very constant. 
Whereas in samples of mixed milk the sum of the first substances 
varied between 5 and 8 . 585 per cent, the differences for the total 
dissolved substances were only 6.05 to 6.25 per cent. 

Milk serum which contains the dissolved substances, offers 
therefore constant results in the examinations, the same as the 
examinations which lead to the establishment of the fat-free 
solids, which still include the casein. Examinations of serum 
are therefore of the highest practical value for the demonstration 



44 Biological, Chemical and Physical Characteristics of Milk. 



or establishment of the addition of water, provided that the sornm 
is always prepared in the same way. Ackennann, Mai and Roth- 
enfnsser have in their fundamental works, determined tlie practi- 
cal importance of the polarization of the proteid-free serum, and 
have proved that with the polarization of the chloride of calcium 
serum we possess means which are better adapted than any other 
to the detection of the adulteration of milk by water. Refrac- 
tion is the most valuable accessory to the various methods of tests 
of recent times. 

Ackermann found in 2,800 samples of normal milk, variations 
in the scale division of Zeiss 's immersion refractometer, from 38.5 
to 40.5. 

Even slight additions of water reduce the refraction con- 
siderably; the addition of 5% of water results in a 1.3 lowering of 
the scale division, while 10% lowers it 2.3. 

According- to Mai and Rothenfusser the original refraction of 
39 scale divisions is lowered to a refraction of : 

37.9 vrith about 4% addition of water 



37.7 


a 




5% 


37.5 


I i 




6% 


37.3 


i ( 




7% 


37.1 


i i 




8% 


36.9 


i i 




9% 


36.7 


i i 




10% 


36.5 


i i 




11% 


36.3 


i i 




12% 


36.1 


I i 




13% 


35.9 


i i 




14% 


35.7 


i i 




15% 


35.5 


i i 




16% 


35.3 


I i 




17% 


35.] 


i i 




18% 


35.0 


i i 




19% 


34.8 


i i 




20% 


34.0 


a 




25% 


33.3 


i i 




30% 


32.6 


( i 




35% 


32. 


i i 




40% 


30.9 


i I 




50% 



In the establishment of the refraction index of the chloride of 
calcium serum it was also discovered that it is impossible to estab- 
lish normal values for the chloride of calcium serum, as well as for 
other constituents of milk. Mai and Rothenfusser also estab- 
lished the general rule for milk, that only in the presence of rigor- 
ous controls of the same origin can the addition of water be 
satisfactorily determined, and the extent of the adulteration 
established. 



Ferments in Milk. 45 



The experiments of Weigner and Yakuwa are of interest since 
they demonstrate that the refraction and specific gravity of the 
chloride of calcium serum are theoretically of equal value. Mai 
and Rothenfusser, on the other hand, emphasize the fact that of 
two theoretical methods of equal value the man in practice has to 
prefer the method which offers, with the same certainty of the 
results, greater advantages in regard to rapidity, convenience, 
and saving of material, advantages which the method of refrac- 
tion possesses. 

The investigations of Mai and Eothenfusser prove that the 
variations in the results of continued tests, from day to day may 
reach in mixed milk of one stable . 1 to . 55, and in longer periods 
( 22 days ) , up to 1 . 0. Changes of feeding have no marked influence. 
The milk of individual cows failed to show any important fluctua- 
tion during the time in which the tests of the entire stable Avere 
made (0.2 to 0.6). 

More considerable may be the fluctuation between the find- 
ings of normal milk and the secretion from cows Avith an affected 
udder, and the variation between the findings of milk from the 
same animal while healthy, and within 24 hours after the udder 
becomes diseased. 

The milk of individual animals with affected udders shows, 
not infrequently, values which are considerably below the values 
of normal milk. This has been proved by the work of Metz^ger, 
Fuchs, Jesser and Henkel, and from the experience of the official 
milk control station. 

These abnormal values, however, do not affect the worth of 
this method, if the results are compared through the use of satis- 
factory control tests, and confirmed by other methods. 

Ferments in Milk. Immune Bodies. 
Milk as Antigen. 

For the testing of milk special characteristics which it pos- 
sesses, which may be collected under the name of reaction manifes- 
tation of ferment action, and for which at present there is still 
no satisfactory explanation, are of importance. 

Under the term ferments (enzymes) those substances are 
included which hasten chemical changes with an explosion-like 
rapidity (Uexkuell), and without using themselves up they act in 
relatively minimal quantities. Their activity is inhibited by the 
products of the reaction. Higher degress of heat and certain 
toxins (ferment toxins, as for instance hydrocyanic acid) inhibit 
their activity, the ferments being thermolabile. The author desig- 
nates as ferments all of those bodies with ferment-like action, with- 
out consideration as to whether the nature of the ferment is known 
or not. 

A careful distinction must be made between original fermen- 



4G Biolotiical, Clieinical and Pliysical Characteristics of Milk. 

tative action and fcrniont-like bacterial activity sometimes taking- 
place in milk. 

The original "ferments," the natnre of which is disputed, 
originate from the blood, or are formed from the cells of the blood 
and the parenchyma of the ndder. They are either eliminated the 
same as products of metabolism into the surrounding parts, or 
they are anchored to the cell and are only set free in the breaking 
up of the cell (ecto- and endo-ferments). The ferments in their 
action are destined to certain substances to which they fit, "as the 
key fits the lock" (Fischer). They act either through hydrolytic 
splitting, through oxidation, or through reduction. 

Those ferments are of importance to the milk inspector, where 
diminished or increased presence or complete absence offers cer- 
tain conclusions as to various conditions in the udder or in the 
milk. These are the amylase (diastase), the indirect oxydase (per- 
oxydase), the superoxydase (catalase) and the indirect reductase 
( aldehydreductase, ' ' aldehydcatalase " ) . 

Besides those mentionefl, milk also contains other bodies whieli are included among 
the ferments; for practical milk examinations, however, they have little or no bearing. 
Mention need only be made here of the proteolytic ferment, " Galacta,se," found by 
Babcock and Eussell and bodies acting like pepsin or trypsin (Jensen, Freudenreich, 
Spolverini and others). These are only present in very small amounts. Kinase and 
fibrin ferment have also been demonstrated in milk. 

The proteolysis could be explained through the presence of leucocytes in the milk. 
Similar to the proteolytic ferments which cannot be utilized for diagnostic purposes, 
the lipase and the salol-splitting salolase (the existence of which as a ferment is dis- 
puted by Desmouliere, Miele and Willen ; the alkaline reaction of various kinds of milk 
is sufficient to split up the salol) can not be likewise utilized for the purpose of di- 
agnosis. Rullmann in 1910 proved by the examination of aseptically drawn milk, that 
salolase is not an original ferment; the author considers the splitting of the salol to be 
the result of bacterial action. 

Of the ferments in milk which split up the carbo-hydrates, the 
amylase (diastase, galactoenzyme), whose action is similar to the 
ptyalin of saliva splitting up the polysaccharid starch into dex- 
trose and maltose, is of the greatest interest (Moro). This fer- 
ment was first found by Bechamp in the milk of women, later by 
Zaitscheck, Koning, Seligmann and others in cow's milk. One 
hundred c. c. of mixed milk can be split up b}^ 0.015 to 0.020 gm. of 
amylase. Amylase is destroyed by heating for 30 minutes at 68 
deg. C. (Koning) ; the optimum of its activity lies at 45 deg. C. 

The substances designated as oxydase and peroxydase exert a special action. They 
transmit the oxidation either by "activation of the oxygen of the air," (direct oxida- 
tion) or by abstracting the active oxygen, for instance from peroxide of hydrogen (per- 
oxydase). Substances acting as reagents indicate their oxidation by the formation of 
coloring matter. 

The occurrence of direct oxydase in milk, the action of which 
appears even without peroxide of hydrogen, is uncertain. Rull- 
man has found traces of direct oxidation in milk drawn under 
sterile conditions ; the quantity however is almost nil for practical 
purposes. 

The indirect oxydase acts only after the addition of hydro- 
gen peroxide or other oxygen carriers (for instance super-borates), 



Catalase. 47 

by abstracting active oxygen after the formula HoO.^H.O+O 
(Jensen). The active oxygen oxidizes the added ''chromogenic" 
substances, as guaiacol, ursol, paraphenylendiamin, etc., to coloring 
matter. The peroxydase is injured by long heating, even at the 
relatively lower temperature (50-60-70 deg. C), and is destroyed 
at about 75 deg., so that boiled or pasteurized milk may be dis- 
tinguished from raw milk by the non-appearance of the color 
reaction. 

The action of the superoxydase (Raudnitz) or catalase 
(Loew) develops in a different way. It splits the HoOo according 
to the formula 2 llo0o=2 H.O+aO, which join to a molecule of 0.. 
Other authors include the superoxydase with the oxidizing fer- 
ments, as the freed oxygen is utilized in the body for the oxidation 
(Seligmann). According to others it is included with reductase, 
as the action of the ferments on H.^Oo equals a reduction of 2 HoO, 
and molecular oxygen O2 which passes out without being utilized 
for oxidation, whereas the oxygen freed by peroxydase is imme- 
diately utilized for further oxidation changes ; therefore the per- 
oxydase is an oxidyzing, while the catalase is a reducing ferment 
(Grrimmer). 

Original catalase has been demonstrated in the milk of all 
animals ; it originates in the cells of the milk gland, especially from 
the leucocytes. It is secreted, but may be set free in the breaking 
down of cells or may appear bound to the cell. That catalase is 
derived from the cells (especially leucocytes) is not contradicted 
by the fact that cream is richer in catalase than skim milk since 
leucocytes and other cells are also included in the separation of 
the cream. These conditions were indicated by Friedjung, Hecht 
and Pallazzi, and later confirmed by Koning. This also explains 
the reason for the centrifuge foam, rich in leucocytes, giving such a 
strong reaction. Since the formed elements (cells) are precipitated 
with the casein, and probably a part of the free ferment is also 
drawn down with it, milk serum is always poorer in catalase than 
the original milk. 

Catalase passes through infusorial earth filters, but consider- 
able quantities are retained. Light, storage, etc., affect catalase, 
even it it is relatively resistant. A leucocytic extract, which was 
kept exposed to the light in the laboratory of the author, showed 
even after months, an unweakened action to HoOs, while hydrogen 
sulphide, hydrocyanic acid, potassium cyanide, mercuric cyanide 
barium nitrate, hydrochloric acid, sulphuric acid, acetic acid, 
oxalic acid, and potassium nitrate affected its action (Faitelowitz). 
it appears noteworthy that H3O2 inhibits the ferment in its action, 
in the presence of excessive amounts of peroxide of hydrogen the 
terment splits up less H,0. than if the diluted peroxide ofVdro- 
gen IS gradually added. 

Heating to 62-70° C. destroys the original catalase in a short 
time, ihe optimum temperature appears to be about 37 deg. C. 



48 Biological, Chemical and Physical Characteristics of Milk. 



An original "ferment," the nature of wliicli is by no means 
definite, is Scliardinger's formalin methylene blue reductase, which 
according to .Tronmisdorff, will be designated as Schardinger's 
ferment (synonyms are indirect reductase, aldehydcatalase, alde- 
hydreductase). Fresh milk in a mixture of formalin and aqueous 
methylene blue sohition (Schardinger's re-agent), is decolorized 
inside of a few minutes. Smidt explains the action of Scharding- 
er's ferment by the fact that the formalin changes into formic acid 
and thereby reduces the methylene blue. The character of its 
action however is not yet solved. The Schardinger ferment exerts 
its best action, at Cw to 70 deg. C, it is destroyed above 70 deg. As 
has already l)een indicated by Smidt and confirmed by Tromms- 
dorff, Schardinger's ferment is very sensitive. It is injured b^^ 
small excesses of formalin, and by relatively larger quantities it 
is destroyed. 

Romer and Sames established more recently, the interesting: fact that boiled milk 
■with 0.3 c. c. of a 1% of ferrosulpliate solution also s'ives the reaction, and this disap- 
pears again when the mixture is boiled for a half hour. The authors point to the care 
■ndiich must be taken in judging' the so-called enzyme reaction, since it is possible, with 
the aid of simple chemical reagents, to produce similar effects to those obtained in 
the supposed enzymatic reaction. 

Very little is known relative to the origin of the formalin re- 
ductase in milk. This ferment is not in every sample of milk, being 
frequently absent in milk from an animal whose off-spring is still 
sucking, and in animals which are just fresh in milk (Schern). It 
is absent when the time of milking is over-extended, and in stasis 
of the milk (Romer and Sames), and it does not decolorize, or only 
incompletely so, in the first part of the milking, better in the 
middle of the milking, and rapidly in the last portion of the milk- 
ing. This also corresponds to the relative frequency of fat in 
milk but no one however has been able to establish a complete par- 
allelism. The authors conclude from this that the same conditions 
under which the gland excretes especially large amounts of fat, 
cause the quantity of Schardinger's ferment to be likewise in- 
creased. 

Milk as Antigen and Carrier of Anti-Bodies. 

Since the fundamental experiments of Ehrlich relative to the 
formation of immune substances in the animal body, we possess an 
explanation for manifold manifestations between the inter-action 
of the disease-producing agent and the animal's power of protec- 
tion, known as Ehrlich 's theory of immunity. 

The substances which are formed in the body in the com- 
l)at against certain invaders are the anti-bodies ; the harmful sub- 
stances which are capable of stimulating the body to the formation 
of anti-bodies are the antigens. 

Antigens may be substances of the most varied kinds ; animal 
proteid, animal cells, plant cells, plant proteid, living and dead bac- 
teria, bacterial substances, toxins, etc. The antigens are distin- 



Antigen Action. 49 



guislied by groups, wliicli make possible their combining with cer- 
tain groups of the cell substances of the body. The "haptophore" 
groups of antigens under certain conditions fit as a key fits the 
lock, into the haptophore group of the "receptors," thus making- 
possible the binding of the antigens to the cell. These terms were 
applied to these bodies by Ehrlich. 

_ The simplest way of explaining the mechanism of the antigen 
action and the anti-body formation is by using toxin as an example, 

A toxin is an antigen with a haptophore binding group, and a 
poison-producing group, the toxophores. If the toxin enters the 
body of an animal it may find groups on the cell to which it fits, 
the so-called receptors, which bind its haptophore group. If this 
has been the case the toxophore group exerts its action, the effect 
of the toxin becomes noticeable and the animal suffers as a result 
of the toxin. If there are no receptors present for the specific 
toxin it is impossible for the toxin group to exert its action, and 
the animal is therefore resistant against this respective toxin. 

It is possible that as a result of the receptors of the cell com- 
bining with the toxin, the cell molecule is destroyed. But if the 
damage is not too serious, the protoplasm is stimulated to produce 
numerous receptors, — an over-production in fact. As not all of 
these are necessary for the performance of the cell function, the 
superfluous ones are rapidly thrown off into the body fluids. If 
such free receptors combine with the haptophore groups of the 
toxin, the latter is no longer able to combine with the protoplasm 
of the cell. These free receptors therefore protect the body against 
renewed action of the toxin, that is they act as antitoxins, and con- 
stitute the antitoxic part of the serum. 

Besides the antitoxins, the action of which lies principally in 
the neutralization of the binding group of the toxin (anti-bodies of 
the first order), there are still more complicated receptors, for 
instance those which possess an active or ferment-producing 
group ; they are anti-bodies of the second order. Finallv there are 
anti-bodies of the third order, which are unable to act by them- 
selves, but must utilize a third body in order to exert an action on 
the antigen. 

^ Immune bodies of the third order become complete in their 
action, only through the utilization of the complement. These im- 
mune bodies of the third order possesss therefore a binding group 
for anchoring the antigen, and a binding group for the complement. 
They are amboceptors, in contradistinction to the uniceptors of the 
first and second order. 

Some anti-bodies resist heating for a half hour at 56 deg. C; 
they are thermostabile, as for instance the antitoxins, the agglu- 
tmms, the amboceptors, while others, as for instance the comple- 
ment, are destroyed at this temperature, as they are thermo-labile. 

, , . ^^' /^^ instance, hemolytic anti-bodies are produced in a rabbit by treating the 
rabbit with red-blood corpuscles of another animal, then the hemolytic rabbit serum 
lo-^es its action by heating to 56 deo-. C 



50 Biological, Clieuiical and Physical Characteristics of Milk. 

The red blooil corpuscles however are again dissolved when to the heated, "inacti- 
vated" rabbit serum, guinea-pig serum containing complement is adde<i. Therefore, 
whereas neither the ambocejitor in itself, nor the complement in itself can dissolve 
blood corpuscles, the combination of the two is capable of doing it. 

The action of the anti-body is specific for the snl)stance which 
induced its formation, on homologous antigen. Diphtheria anti- 
toxin acts only on the toxins of the diphtheria bacillus, and not on 
the toxins of the tetanus bacillus. The specificity is a very high 
one, nevertheless it is only relative; that is, a similar, although 
somewhat weaker action is exerted on related antigen, as compared 
with the specific antigen. 

The chemical structure of the anti-bodies is unknown, and 
they are generally designated according to the action which the/ 
exert in the animal body. 

Anti-toxins neutralize toxins, agglutinins agglutinate (stick 
together) animal cells and bacteria, and drag them to the bottom, 
precipitins and coagulins produce precipitation in antigen solu- 
tions, hemolysins dissolve erythrocytes, bacteriolysins dissolve 
bacteria, cytolysins dissolve animal cells, etc. 

If anti-bodies are produced by injecting antigens into an an- 
imal, then the animal is actively immunized against the antigen. 
On the other hand, if another animal is injected with the produced 
anti-bodies it is given a passive immunity. The active immunity 
lasts for a long time, the passive immunity does not last beyond 
several weeks. 

If anti-bodies are present in the blood in certain quantities 
they are excreted by the milk gland, and may be demonstrated in 
the milk. 

Ehrlich succeeded in proving the passing of anti-toxins into 
the milk of anti-toxic immune mothers, by showing that young" 
mice from non-immune mothers acquired a high degree of resis- 
tance against the toxin when they were allowed to suck actively- 
immunized mothers. 

The passing of anti-bodies into the milk even in the presence 
of passive immunity w^as proven by Ehrlich, Schmidt and Pflauz, 
although the passage was only slight. The action of such milk was 
15 to 20 times weaker than that of the blood. 

Similar to the action of the anti-bodies of the first order are 
those of the uniceptors of the second order; for instance, bacterial 
agglutinins and precipitins. The passag-e of agglutinins from the 
blood into the milk has been demonstrated by Kraus, in goats which 
had been immunized against colon-bacilli, t^^phoid and cholera. 
The later works of Bensaude, Bertarelli, Bamberg and Briigsch, de 
Blasi, Courmont, Cade, Figari, Maragliano, Eodella, Staubli and 
others confirm the findings of Kraus. The agglutination value of 
milk, as compared with blood, may be lower or identical, or it may 
even be greater than that of tlie blood. As it has been found that 
bacterial agglutinins may pass into the milk, so it also has been 
proved that agglutinins against animal cells may do likewise. 



Complement Content of Milk. 5^^ 



That under certain conditions amboceptors, as immune bodies 
of the third order, may pass into the milk, is proved by Bertarelli's 
experiment on a sheep treated with the red blood corpuscles of a 
chicken. The specific hemolytic amboceptor which resulted could 
be demonstrated in the milk. Therefore although amboceptors 
may^ pass into the milk and although normal mifk contains non- 
specific hemolytic amboceptors in small amounts, nevertheless the 
passing of hemolysins into the milk is very uncertain. According 
to Kraus, Kopf and others hemolysins do not occur in milk ; like- 
wise bacteriolysins are absent, or their presence is very doubtful, 
according to the investigations of Bab. Of course one of the 
hemolytic factors, the amboceptors, might be present in the blood, 
while the complement under the special conditions present in milk, 
may be inactive. 

While Pfaundler and Moro state that hemolytic and bacterici- 
dal complement may be found in cows ' milk, Bauer and Kopf, and 
Bauer and Sassenhagen, on the other hand showed that in normal, 
ripe milk complements are not present; that is, even by special 
examinations only traces could be established. 

On the contrary in samples of colostral milk, and milk from 
udders affected with mastitis, both amboceptor and complement 
may be demonstrated. 

The complement content of milk drops with the duration of 
time which has elapsed between parturition and the taking of the 
sample, until from the sixth to the twenty-seventh day after calving 
the amount of the complement disappears. 

This observation may possibly be of great practical value in 
ascertammg whether or not a cow is fresh in milk. Mastitis milk, 
which bears a close relation to colostral milk, showed a relative 
richness in amboceptor and in complement, thereby making it pos- 
sible to establish the affection of the udder by the demonstration 
of the complement. Of course it is not certain that the comple^ 
ment occurs early enough to enable this method to be utilized more 
readily than for instance the Trommsdorff test, the catalase test, 
or microscopic examination of the centrifuged sediment, and 
others. 

Sassenhagen found in one case that the presence of mastitis 
could be determined by complement-fixation 18 days before the 
first clinical appearance of the disease, even when the quantitv 
of sediment, after the Trommsdorff reaction was insufficient to 
afford a basis for a diagnosis of mastitis. 

Bauer further proved that complement inhibiting substances 
are present m milk ; Hausmann and Pascucci traced this inhibition 
of hemolysis to the presence of lecithin or cholesterin in the milk. 
^ According to Kopf the complement passes from the colostral 
milk into the blood of the calf; it may be demonstrated in the serum 
of the calf from the third to the fourth day, before which time the 
blood cells of guinea pigs were not dissolved. 



52 Biological, Chemical and Pliysical Characteristics of Milk. 



As j)roved by Kraus bacteriolytic inimuiie bodies also pass into 
the milk, in artilicially immunized animals, and into the body of the 
sucklino- consnmini;* the milk, provided the mother possesses active 
immnnity (de Blasi). 

Of other immune bodies which are present in the blood and 
have been demonstrated also in the milk of the same animal, should 
be mentioned the opsonins (Wright), which influence the bacterins 
in such a way that they may be readily assimilated by the phago- 
cytes (Turton and Appleton, Eisler and Sohma). 

Other substances which induce the so-called hypersensitive- 
ness (anaphylaxis), have also been demonstrated (Otto). At 
least it has been proven in the study of hypersensitiveness, that 
the off-spring- of hypersensitized guinea pigs possess an increased 
sensitiveness for homologous antigens, and this may not only be 
the result of the intra-uterine transmission of the anaphylaxis 
from the mother to the young, but also of the transmission of the 
immune bodies, through the milk of the mother. 

To the subject of immune substances belong possibly the ob- 
servations made by Tage, Duhat and Dobrowits, during the treat- 
ment of nursing syphilitic mothers with salvarsan Avhich sho^ys 
its effect upon the untreated syphilitic children. Syphilitic chil- 
dren thrive splendidly after the treatment of their mother. It 
was impossible to demonstrate arsenic in the milk, either in or- 
ganic or non-organic combination, Ehrlich explains the action 
by the fact that a rapid breaking down of the syphilitic spiro- 
cliaetes in the mother is produced through the action of the new 
syphilitic remedy, and thereby an elimination of the endo-toxins 
is induced. The antitoxins which develop in the mothers pass into 
the milk, and cause a passive immunization of the child, through 
the gastro-intestinal tract ; Jesionek, on the other hand claims the 
passage of the arsenic from the blood of the treated mother to the 
milk, and explains thereby the remarkable results in untreated 
children which are nursed by the treated mothers. 

Very little is known with certainty relative to the quantita- 
tive relation which exists between the innnune bodies appearing 
in the circluating blood, and those in the milk. The views expressed 
are too widely divergent. It is known of the anti-toxins in which 
this relation has been mostly studied, that of 15 to 30 parts of the 
anti-bodies which are demonstrable in the blood a certain amount 
appears in the milk. 

These relations are still somewhat vague, since the passing 
of the anti-bodies which are bound to the albumins and globulins 
depends on the quantitative relation of these proteids in the milk, 
and the experimental results therefore must vary in accordance 
with the species of animal used, the stage of lactation of the 
respective individual, diseases of the udder, etc. 

In infections of the udder, for instance with colon bacilli, anti- 



Agressins. 53 

bodies accumulate in the glands so tliat as a result the milk serum 
agglutinates more readily than the blood serum. 

Not only anti-toxins and other protective immime bodies pass 
into the milk, but substances also which inhibit the protective 
power of the body, for instance aggressins, at least so long as the 
body has not formed anti-aggressins. The aggressins for instance 
act against the dissolving of bacteria. Schenk demonstrated anti- 
staphylolysins and anti-vibriolysins in the milk of goats, cows and 
women. 

Otherwise the passage of toxic substances of the character 
of antigen, which are closely allied to proteids, could be just as 
plausible as the passage of the constituents of the blood which are 
indispensable in the composition of the milk. The passage of 
toxins into the milk has not yet been satisfactorily proven for all 
toxins. 

A large number of known substances from animal and plant 
life are known as toxins, that is, bodies which do not act like 
cliemical poisons, but exert their toxic action only after a period 
of incubation, in which time fixation takes place. 

These toxins do not affect all animals in a similar degree, 
but only those which are susceptible. Certain species of animals 
are not susceptible to certain toxins ; they are immune. This im- 
munity may also be artifically established in susceptible animals. 
The toxin is an antigen, and under certain conditions it produces 
an anti-toxin contrary to the toxins which act purely chemically. 

Among toxins acting in this manner may be mentioned the 
products of metabolism of the Bacillus diphtlierice, the Bacillus 
tetani, the bacillus of certain forms of meat poisoning — the 
Bacillus hotulinus and the Bacillus pyocyaneus, the bacillus of 
blackleg, and the body substances of certain bacteria (endo-toxins). 
They may be of animal origin : snake toxins, spider toxins, scor- 
pion toxins, turtle toxins, toxin of the blood of eels, salamander 
toxins, wasp toxins, or of plant origin, such as the abrin, robin, 
krotin, ricin, etc. 

If it is considered that the gastro-intestinal tract of very 
young individuals is readily penetrable for proteids, although pro- 
teids of unlike origin pass with greater difficulty than those of like 
origin, the question as to whether the milk of the mother may con- 
tain toxins when toxins are circulating in her blood, assumes prac- 
ticalimportance. This becomes, however, unimportant when it is 
considered that even in severely affected individuals only verv 
small quantities of toxins are circulating free in the blood. Should 
a part of these minute amounts be secreted in the milk, this quan- 
tity itself is of only little practical importance even when the great 
susceptibility of the intestines of the suckling is considered. 

It is true that Miessner succeeded in proving that mice die 
from tetanus when they are fed with raw milk from a cow affected 
with tetanus, whereas the feeding of meat has no influence on the 



54 Biological, Chemieal ami Physical Characteristics of Milk. 

health of the animal ; this proves the passage of the tetanus toxin 
into the milk. 

Older animals do not become affected even after the adminis- 
tration per OS of large doses of toxins, at least not from diphtheria 
or tetanns toxins, and the Bacillus hotidi)ti(S, the toxins of which 
are absorbed by the stomach bnt the bacillus does not thrive in the 
body; therefore the possibility of secreting these toxins through 
the milk gland is from the lirst of small importance, especially 
since in severely affected animals the secretion ceases. 

From a practical consideration of the question of toxin elimi- 
nation, the plant toxins come principally into consideration, espe- 
cially ricin, as food adulterations to a great extent take place with 
ricinus seed and its flower. An elimination of ricin with the milk, 
however, has not been observed up to tlie present time. Ehrlich 
was unable to observe an elimination of ricin in mice which were 
under the action of ricin ; the offspring of- these mice Avere not 
actively immunized against ricin but acquired only a passive im- 
munity of short duration. 

Of more importance however are the bacterial toxins, and 
products of decomposition acting like toxins, which subsequently 
develop in the milk after certain fermentation processes. 

The above-mentioned immune substances are probably of great 
importance for the nourishment of the young and the sucklings. 
The passage of genuine proteicls in very young individuals with 
injured mucous membranes, is an established fact, and with the 
globulins anti-bodies also pass into the blood of the young, while 
in older individuals the relatively labile anti-bodies are changed or 
destroyed by the splitting up of the proteids. 

The absorption of anti-toxins through the intestines of the 
young has been proved by the classical experiments on sucklings 
by Ehrlich. 

Other works by Brieger, Ehrlich, Salge and Romer prove that 
certain immune substances of milk of like origin pass through the 
intestines, while in feeding sera or anti-substances of like origin 
contained in milk of unlike origin the quantity passed was only 
very slight. Thus Romer succeeded in demonstrating passive 
immunity in foals after feeding them with anti-toxin milk of like 
origin, but was unsuccessful after feeding anti-toxic sera of like 
origin. 

In calves of course the results were positive even when the 
anti-toxin was mixed with the milk as a serum of unlike origin, but 
the quantity of immune bodies of unlike origin absorbed was 
smaller than that of like origin. The absorption diminishes with 
the increase of the age of the animal. 

Relative to the passage of other immune substances from 
the milk into the blood of the suckling, the same experiences hold 
as a rule as in the case of milk containing anti-toxin. 

Milk is not only a carrier of anti-bodies, and possibly of anti- 



Table I. 




Acute purulent fibrinous mastitis. Dilation of the blood vessels (c) ; with exudate of 
numerous cells into the alveoli and excretory duct. Hematoxylin — Sudan III. 




Concrement .formation in milk stasis (a), and in mastitis (b) ; inactive portion of the 

gland (c). 

Ernst, Milk Hygiene. 



Precipitin. 55 

gen, but as a proteid-containing material it is an antigen in itself, 
or rather a collection of antigens, which may again produce anti- 
bodies in the body of an animal. These anti-bodies against milk 
not only develop in artificial administration by injections, but also 
under certain conditions during the natural ingestion of the milk 
per OS as a food. Although usually such anti-bodies against nutri- 
tive proteids of unlike origin appear only in intensive over-feeding 
of proteids (Ascoli, Michaelis and Oppenheimer, Uhlenhuth, and 
others), nevertheless in the presence of an injured intestinal 
mucous membrane the absorption of proteids of unlike origin may, 
under natural conditions, take place, and thereby induce the for- 
mation of anti-substances. 

Moro succeeded in finding cow milk precipitin in two instances, 
and milk proteid in one instance in an examination of 22 anemic 
bottle-fed children. 

Bauer found precipitating substances of cow's milk in the 
blood of an emaciated man, 

Kentzler, with the aid of the precipitation test, demonstrated 
milk proteids in the blood of six human subjects in which the gas- 
tric secretion was disturbed, out of 61 cases that he examined two 
to three hours after feeding. 

Although milk is absorbed through the intestines of older 
individuals only after the splitting up of the proteids, nevertheless 
in case of an injured mucous membrane, or in greatly emaciated 
and in very young individuals the direct absorption of unchanged 
proteids is possible. Ganghofner and Langer succeeded in proving 
this on very young rabbits, on pigs and on newly born cats, and 
they succeeded also in demonstrating a precipitin formation in the 
blood. Schkarin describes similar results after the feeding of 
cow's milk to young rabbits. 

Lactoserum. 

It will be advisable and appropriate to include at this place 
a subject which as a matter of fact belongs to the chapter dealing 
with the characteristics of the milk of various species of animals. 
Milk is an antigen and contains various antigens. After injecting 
the milk of species A into an individual of species B, the formation 
of various anti-bodies, precipitins, amboceptors, etc., may be ob- 
served in the blood serum of the treated individual, which gives 
to the blood serum the specific characteristics of lactoserum. This 
specific characteristic is shown by the fact that the cow lacto- 
serum of rabbits produces a precipitation only when cow's milk 
is used for the precipitation, but not with milk of women or goats. 
Works of Bordet, Fish, Morgenroth, Wassermann and Schiitze 
show the specific action of lactosera. With the aid of such sera 
the possibility is afforded of differentiating the milk from various 
species of animals. 



56 Riolojiical, Chemical and Physical Characteristics of Milk. 

This however does not end the degree of the specificity, as it is possible with the aid 
of the ])recipitation method to ditferentiate various kinds of i)roteids of one and the 
same milk. If tiie soluMe i)roteid bodies are sejiarated from the undissolved casein by 
filtration (Schlossmann), then the rabbits which are treate<1 with solnble proteid bodies 
furnish sera which react only to milk albumin and globulin (Hamburger). 

It is of fnrtlier interest that cow-casein sera gave precipitation 
with cattle blood (Hamburger), the same as is the case with lac- 
tosera (Landsteiner, Halban, Diingern, F. Meyer, L. Aschoff). 

Moreover lactosera immobilizes spermatozoa of bulls, and 
dissolves red blood corpuscles of cattle. However no reaction 
results from the addition of cattle blood serum containing anti- 
bodies to cow milk (Meyer), The anti-serum sensitized against 
cattle blood only gives slight precipitation when it possesses espe- 
cially high value (Uhlenhuth and Schiitze). The same conditions 
were found in preparations of human blood, and women's milk, hj 
Halban and Landsteiner. 

Uhlenhuth and Schutze proved that the differentiation of 
various kinds of milk shows that the biological method succeeds 
even when the milk is heated to a high temperature (114 deg. C. in 
an autoclave) ; if the milk antigen was heated 20 minutes at 120 
deg. C, lactosera resulted, which only contained coagulins, but no 
hemolysins. Sion and Laptes showed that the most varied splitting 
and decomposing changes of cheese-making and cheese-ripening 
do not influence the antigen to such an extent that the kind of milk 
used in making the cheese could not be determined by the biological 
method. This specificity is of course manifested even in the use 
of lactosera, but is not absolute, only relative. Lactosera also gave 
a reaction with the milk of closely related animals, the same as 
has been established for blood sera, meat sera, etc. Thus for in- 
stance it is impossible to ditferentiate sheep's milk from goat's 
milk (Uhlenhuth, Moro, Gengou), although it is possible to draw 
conclusions from the comparison of the intensity of the reaction 
in the homologous milk. 

Other authors, as for instance Bauer, succeeded in demonstrat- 
ing by the so-called complement-fixation method, the presence of 
cow's milk in woman's milk, even when only 1 c. c. of the former 
had been added to 1000 c. c. of the latter. 

If specific serum wdiich has been heated for a half hour at 57 
deg. C. is mixed w^ith milk and as much complement is added as 
is necessary for the dissolving of the subsequently added blood 
corpuscle suspension, Avith the aid of certain quantities of hemo- 
lytic amboceptors, then the amboceptors of the lactoserum bind the 
complement, provided they find in the milk the specific antigen 
(cow lactoserum-cow milk), and the subsequently added hemolytic 
system, free of complement, no longer finds complement, so hemo- 
lysis does not occur, but instead fixation of complement results. If 
there is no specific antigen present (if the milk to be examined con- 
tains no cow milk), the complement remains free to be utilized 
later by the hemol3d:ic amboceptors and the blood cells, for the 



Anopliylaxia. 57 

functionating hemolytic system, and a solution of the blood — hemo- 
lysis — results. 

The appearance of ''anaphylaxia" may also be produced ex- 
perimentally with milk (Arthus and Besredka). It may be brought 
on by raw as well as by boiled milk. 

The phenomenon of hypersensitiveness as is known, results when a proteid of un- 
like origin is injected into an animal and later after a period of time the same proteid 
is re-injected. At the second injection (or only after later ones, depending on the ex- 
perimental animal and the quantity of proteid), the experimental animal reacts violently 
with indications of extreme sickness (Von Behring, Richet and Arthus), which may even 
result in death from convulsions and pulmonary edema. 

Miessner succeeded in producing a hypersensitiveness against 
homologous kinds of milk in guinea pigs, sometimes after one in- 
jection, but more markedly after repeated subcutaneous injec- 
tions, and with the greatest certainty after intra-abdominal in- 
jections of small quantities of raw milk. The best reaction was 
obtained in the animals after three intra-abdominal injections 
of .5 c. c. of milk, on three successive days. After the preparation 
of the animal 40 to 50 days should elapse before the test which is 
made by intra-cardial injections. 

After repeated injections it is possible to demonstrate an ana- 
phylaxis in most cases even with boiled milk. 

In order to utilize the biological test for milk ditferentiation 
several rabbits should be prepared. This is carried out by in- 
travenous injections of small quantities (5 or more c. c.) of milk 
heated for a long time to 65 deg. C. The injection is repeated 5 
to 8 times at intervals of 1 to 4 days. In from 14 to 20 days after 
the last injection the lactoserum may be tested for its effectiveness 
and if found suitable, may then be drawn. For this purpose the 
anirnal is kept without food for one-half day, (in order not to 
obtain a cloudy serum), a venous hyperemia of the ear is produced 
by intensive lighting of the ear with the aid of an electric globe, or 
by rubbing it with xylol, and the vein is then punctured with a 
fine hypodermic needle. Several cubic centimeters of blood are 
drawn, which is allowed to coagulate ; the blood clot is separated 
and allowed to stand for 24 hours in an ice chest. The test is made 
as follows: 

1. Establish the dilutions of the serum which are capable 
of producing a visible precipitation in 3 c. c. of milk dilution, with 
1:60 physiological salt solution, or 

2. Establish the dilution of milk with 1 :10 physiological salt 
solution, in which when mixed in the relation of 1 :6, the lacto- 
serum still produces a precipitation. 

The most active lactoserum is the best adapted for use. 

The rabbit is bled to death (slight anesthesia-opening of the 
thorax-puncturing of the heart), the blood for the collection of the 
serum is allowed to stand, the serum is dra^vn off in quantities of 
2 to 5 c. c. into small vials, and placed in an ice box for safekeeping. 



Chapter Y. 

PROCUREMENT OF COW'S MILK. 

As lias already been mentioned milk secretion may be retained 
for a long time by proper emptying of the gland and by the stimu- 
lation exerted on the gland in the process of emiotying. In the 
joresence of incomplete milking, in over-extending the time of 
milking, and in stasis of the milk, a condition of the gland results, 
which finally passes into a state of inactivity, Avlien the stimulating 
condition which is exerted by the retention of the secretion on the 
secreting epithelia does not again appear with the act of a com- 
plete milking. The milk secretion therefore is largely dependent 
on the activity which is exerted on the gland from the outside, such 
as the sucking act of the calf, or artificial milking. 

Artificial emptying is carried out in various ways: 

1. By closing the upper portion of the teat with the aid of the 
thumb and index finger, and pressing out the contents of the cis- 
tern by gradual closing of the hand to a fist in such a way that first 
the middle finger, then the ring finger, and finally the small finger 
presses the milk downward and from the opening of the teat. The 
open hand is passed up again, forcing the milk into the cistern from 
the upper part of the quarter, the thumb and index finger again 
squeeze the cistern at its base, and the procedure ends as before. 
This manipulation is known as "fisting" or full handed milking. 

2. By stroking with the closed thumb and index finger from 
the base of the teat to its point the milk may also be pressed out 
(''stripping" or ''tipping"). This method of milking requires 
much less strength than the full handed milking, but causes a 
lengthening of the teats, and is a painful operation for the animal, 
as it is frequently accompanied by injuries to the tissue, and tear- 
ing of tlie mucous membrane. 

The full handed milking may be carried out by dry milking, 
while "stripping" succeeds only when the teat and hand are 
moistened (moist milking), since the necessary smoothness and 
slipperiness of the skin result only from moistening. 

If the teat is not pressed with the extended thumb (a brace 
for the index finger), but the thumb is crooked and the teat is 
pressed and stringed with the bent index finger against the nail 
surface of the thumb and the knuckle of the joint, this is spoken of 

58 



Methods of Milking. 59 



as "streak milking" or stripping witli bent thumb. The "streak 
milking" may be completed by stripping or by full handed milking. 
Full handed milking and this method combined with ' ' streak milk- 
ing" are according to Henkel permissible; the other kind of 
milking should be prohibited since the teats are too much extended. 

The udder should be milked by the dry method since this 
method of milking is more cleanly than moist milking, in which the 
fingers become moistened by the milk, and although they slip 
easily, at the same time they wash off the dirt from the entire teat. 

It is to be regretted that moist milking and stripping because 
of their labor saving advantages, are preferred by many milkers 
on account of their convenience, and even if they are urged to 
carry out the ordinary dry milking, as soon as they are left with- 
out supervision they will at once fall into the same fault. 

The order of milking the various teats differs. Milking from 
the same side is supposed to induce the development of the side 
first milked, since the half of the udder first milked is worked with 
fresh strength while the subsequently milked quarters are not 
emptied as well on account of the beginning weariness of the 
milker and therefore they develop less perfectly. The hind quar- 
ters are either not emptied entirely when the milkers have com- 
pleted the milking of the fore quarters, or else one hand of the 
milker rests while he finishes milking the hind quarter with the 
other. The same applies in milking the teats crosswise, when the 
hind quarter of one side of the udder is milked at the same time as 
the fore quarter of the other side. Therefore it is advisable to milk 
the fore quarters together and the hind quarters together, and the 
milking should be undertaken first on those quarters which appear 
to be most distended. 

With the drawing of the milk from the udder through milking 
the teats, the complete act of milking is not concluded, as the udder 
has not yet been sufficiently exhausted in its production. The cause 
of this may lie in the fact that the milk cannot be emptied 
by the simple sucking action from the smallest milk ducts and 
alveoli, or that after the apparent entire emptying, the milk pro- 
duction still goes on if the gland cells are properly stimulated in 
their- functions. 

As the flowing in of milk may be accomplished through the 
so-called "preparation," that is stroking or massage of the bases 
of the teats and quarters, the same result is possible through the 
so-called ' ' clean milking, " or " after milking, ' ' to obtain an addi- 
tional quantity, which is especially rich in fat. 

These methods vary and are practiced in different ways in dif- 
ferent localities. 

The best known method of "clean milking," and one which 
has been mostly studied, is that practiced by Hegelund, a Danish 
veterinarian. This method is divided into the following phases : 



50 Procurement of Cow 's Milk. 

1. Milking- through simultaneous full handed milking, first of 
the fore and then of the liind teats, until the milk flows no longer. 

2. This milking is followed by the "clean milking," which 
consists in massaging the udder, beginning at the teat up to the 
base of the teat, and as high as possible extending on to the i^aren- 
clivnia. While the first act corresjDonds with the usual full handed 
milking, the second act massages with a milking motion, the base 
of the cistern, and the third is carried out by surrounding between 
the thumb and the hand, and stroking- down the lower part of the 
quarter, that is, through simultaneous pressing against each other 
of both quarters of opposing sides. 

3. The first manipulation of the after milking is carried out 
by pressing the right quarters of the udder against each other, the 
left hand being placed on the hind quarter and the right hand 
on the fore quarter. In case of a large udder, only one quarter 
is grasped at one time. The hands are then pressed upwards with 
a rubbing motion on the gland which exerts a massage on the par- 
ench^^na of the udder, this being repeated three times, followed by 
milking- out the cistern. This manipulation is repeated until no 
more milk is obtained, when the left quarters are treated in a 
similar manner. 

In the second manipulation the fore quarters are milked by 
placing one hand on the outside of the quarter and the other in 
the division between the two fore quarters. The hands are pressed 
against each other followed by milking of the teats. Then the 
hind quarters are milked by placing a hand on the outside of each 
quarter in such a way that the fingers are turned upwards and the 
thumb placed in front of the hind quarter. The hands grasp the 
quarter and are pressed upward; then they are lowered and the 
milking follows. This is also repeated until no more milk is 
obtained. 

In the third manipulation the milker imitates the butting mo- 
tions of a calf during sucking. The hands loosely surround the 
teats and the quarters are lifted and pushed against the abdominal 
wall so that the gland tissue is shaken. This lifting and pushing 
motion is repeated three times and the teats are then milked 
out. Following this procedure on the fore quarters the hind 
quarters are treated in a like manner, until no more milk is ob- 
tained. 

The works of Aashamar, Alfonsus, Woll, van der Zande and 
Henkel, and Wenk, speak of the excellence of the method of 
Hegelund. 

According to Henkel the increase of the milk yield in 37 
Simmenthal cows was 217.4 gm. (3.4%) per milking on an aver- 
age. Wenk succeeded in obtaining from 24 cows 4.5 kg. of milk 
per day more than Math the ordinary method of milking. 

Of course against the increase of yield must be placed the 



Methods of Milking-. 61 



additional wbrk and time, which is an additional expense and 
considerably diminishes the profit derived from the increased yield 
of milk, and may even nullify it, since it involves the employment 
of additional help. The principal advantages of Hegelund's meth- 
od lie in the fact that the milkers are held down to thorough work, 
and the milk glands are subjected to more correct and appropriate 
handling. 

A modified form of Hegelund's method is the so-called ** New 
Algauer milking method," which combines the acts of the Algauer 
method with those of Hegelund. The massage of each quarter 
is carried out with both hands. The method of Sondergaard aims 
to simplify the time-consuming work of '^ clean milking" inasmuch 
as the residual milk is obtained by a wide extensive hold of the 
halves of the udder at their bases, and pressing at the same time 
and stroking downwards. The principal factor in each method 
of milking is that the udder should be thoroughly emptied, and 
this can only take place when each part of the milk gland is stimu- 
lated by massage to the limit of its production. 



Chapter YI. 

INTERNAL INFLUENCES ON THE CHARACTER 

OF MILK. 

The influences which must be considered in the formation of 
milk may be separated into internal influences which lie in the 
individual characteristics and in the immediate condition of health 
of the animal, and in outside influences, such as stabling, feeding, 
etc., which again act only in that they influence the internal 
condition. 

As internal influences may be considered the characteristics 
of the breeds, strains, family, individual, age, influences of the 
lactation period, pregnancy, and the general and local conditions 
of health. The outside influences may be considered under care 
and attendance, feed, medical treatment, climatic influences, meth- 
ods of milking, etc. 

Following this outline the internal influences on the formation 
of milk will be considered first. 

Breed, Family, Heredity, Individual Characteristics. 



Age, Lactation and Other Special Conditions 
of the Individuals. 

The influence of the breed on milk formation is generally 
known. There are beef breeds which fatten especially well, milk 
breeds in which milk production is especially prominent, and 
breeds which possess the ability to produce both milk and meat. 

Breeds of low lands and their crosses produce more milk 
with lower percentage of fat than breeds from the highlands. Ac- 
cording to the quantity of milk produced, the breeds are headed 
by the Holsteins, Angler, Oldenburger, East Friesian, Breiten- 
burger, Wilstermarscher, Dithmarscher with 20 to 25 liters of milk 
per day per animal at the height of production, with percentages of 
fat from 2.5 to 3 to 3.4. Smaller quantities of milk are given by 
the gra^dsh-brown mountain cattle, the Swiss and Algauer, with 
3.6 to 3.7% of fat, and the spotted mountain cattle, for instance 
Simmenthal, Misbacher and Pinzgauer, with 3 . 5 to 4% of fat. The 
fat content of the Westerwalder and of the Schlesian red cattle 

62 



Influence of the Breed. Q' 



vanes between 3.5 to 3.6%, while the English Shorthorns and 
Ayrshires give 3.7 and 3.8% ; the richest in fat is the milk of the 
Vogelsberger and Harz cattle (3.9 to 4.2%) and that of the Jer- 
sey with 5 to 5.4% (Eamm). Reference should be made here to 
the tollowmg results of tests of production made with Simmenthal 
Vogelsberger, Westerwaldern and Lahn breeds of cows. 

Average weight of the -Simmetithal Lahn Vogelsberg Westerwald 

tested animals 578** 502 427 395 Vp' 

Average production 2495 2650 1919 1878 '' 

Fat contents . 4.001% 4.001% 3.74% 4.1 % 

Individual maximum production 4562 3955 3800 3234 kp- 

For 100 kg. body weight 431.1 528 450 477 4 >> 

*The cow with maximal production stood last year in ninth place. 17 cows pro- 
duced over 3000 kg. each. ^ 

The fluctuation is not in fat content alone, but also in the 
other solid substances. Milk which is rich in fat as a rule contains 
more of the other solid constituents as well. The proportion of 
individual factors of the dry substances is variable; in cattle from 
the highlands for instance, the casein was 76.24% of the dry sub- 
stance, m cattle of the lowlands it averaged 73.78% (Fischer). 

^■f. ^a^^^^i'om the milk of the mountain breeds is generally under otherwise similar con- 
ditions the richest m fatty acid of molecular weight; the fat globules of the brS of the 
lowlands are smaller than the fat globules of the cattle from the highlands Babcock 

ThZZ^fJ''''\"f\'^''T''\''''' P^^^"'^^ '^'^'^ ^^^ ™«r« imfforrLt globules 
than the Holstemswhile_ Ayrshires have small, irregular fat globules in their milk Milk 
with large fat globules is preferable for butter making, since these produce butter of 
good consistence and good taste with a low melting point. proauce outter ot 

The ash content of milk from highly bred animals is some- 
times somewhat lower in CaO and P.O. than that of the common 
breeds but the fluctuation is such that definite deductions cannot 
be established In highly improved breeds Pages found: CaO in 
143 to 0.227% and RO. in 0.18 to 0.273%; in common breeds 
the same elements amount to 0.15 to 0.204, and 153 to '^96 
respectively. '" ' 

These characteristics of breeds are general, but they are not 
so constant that individual strains, individual families, and espe- 
cially particular animals may not present exceptions. This fact 
iSiduS br^'V ^^^^^"^^ ^^^ increased milk production within 

mother was 3 08 tn 3 77% ^!t,'^ T^^ f"™^!" ^^ '""'^^ ^^ ^^^'^ the fat content of the 
Sly-- but i soon as th^: Sf ^^ r?'°* "^ ^^' ""''^^ «^ ^^^ ^^"g^*^^ ^^^-^^^^^^ "^^t^" 
no longer sufficW ?o 5 ff '-^'^^^ or exceeded 3.77%, the influence of the bull was 
maiS lower than i^f^rT/''''?r^t *^' Percentage of fat, and the percentage re- 
tTer'l Lid down by Galt^n f" ^"^'^ experiences of Hogstrom's were^onfirmld by 



54 Internal Innnenccs on the ("liaraeter of Milk. 

The great variation wliieli occurs in the milk production of 
individuals of the same breeds depends on hereditary qualities. 
According- to the statistics of the dairj^ control station at Algau, 
animals of the Algauer breed produce : 

Quantity of Fat Percentage Quantity of 
Milk ■ Fat 

Maximal production 5201 kg. . 4.(i03 181.93 kg. 

Minhnal production 1255 kg. 2.493 45.31 kg. 

Difference 3946 kg. 2.11 136.62 kg. 

Among 50 of the Jeverland breed 

Maximal production 8699 kg. 3.713 286.76 kg. 

Minimal production 2449 kg. 2.482 75.21kg. 

Dilference 6250 kg. 1.231 211.55 kg. 

The production of single individuals during the lactation 
period is sometimes remarkably large. Some of the folloAving 
data relative to production is taken from Kirchner's handbook. 

Pei'centage Quantity 
Author Cow Quantity of Milk of Fat of Fat 

Kirsten Wesermarsch .. 11291 kg. 2.78 , 324 kg. 

5th calving 
Kirsten East Friesian . . 9047.75 kg. 3.07 277.77 kg 



6th calving 



&• "•"' -11.11 XVj^. 



Woll Guernsey 6768 kg. 5.745 388:8 kg. 

''Yeksa Sunbeam" 

Kirchner also quoted a case in which a farmer observed that 
a seven-year old cow in the second month after calving still pro- 
duced 50 liters of milk per day. 

Just as the quantity of milk and percentage of fat may vary, 
so also the fat-free solid substances may vary in the individuals, 
although only mthin narrow limits. The rule also holds good here 
that an individual with milk rich in fat will at the same time pro- 
duce more fat-free solids. 

Normally fed animals which are not individually large pro- 
ducers cannot be brought up to a remarkable increase of produc- 
tion through any agency. The elimination of the poor assimilators 
of food in favor of good producers, which is a matter of economic 
necessity, should be based upon the capacity of the individual cow 
to properly utilize her food. Only through a systematic test of 
milkings and production records can the profits of the dairy be 
increased. 

In judging individuals as milk producers by their external 
conformation, the following rules of the German Society for 
Breeds and Breeding may serve as a basis : 



Influence of Age. 65 



(a) Heavy milk production is usually associated: 

1. With low body weight, 

2. With low measurement at the shoulder, 

3. With a straight back, although slight deviations should 
not be considered as signs of small milk productiveness. 

4. With more or less prominent hips and rump according to 
the characteristics of the breed. 

5. With the more pronounced depth of thorax ; heavy milkers 
are often narrow and flat chested ; 

6. With long shoulders, 

7. With long rumps, 

8. With long, narrow head, 

9. Generally with fineness of horn, 

10. With fine bony structure ; 

11. The most important is the udder. The best cows have 
large udders of spongy-granular consistence, with large tortuous 
mammary veins, large milk wells, and easily movable skin. 

The skin should lay together over the perineal surface of the 
udder in 4 to 6 or more large, well developed folds. The udder 
should collapse thoroughly after milking, and the animals should be 
easy milkers. Relatively early calving seems to have a good in- 
fluence. The possibility of estimating the qualitative production 
of milk from external conformations is only very slight. As a 
rule, as shown by investigations, the smaller and shorter animals 
with fine long bones produce milk of higher quantity, and above 
all milk with a large yield of fat. 

The productiveness of one and the same individual varies, 
especially with age and the lactation period. Cows with the first 
calf, provided normal conditions prevail, do not produce as much 
milk as after subsequent calvings; as a rule when cows reach the 
age of 7 to 9 years with the fifth and sixth calf, the maximum pro- 
duction is obtained. With the advance of age the production 
again gradually recedes. The proportion of solids is higher in 
cows with the first calf than in those which have calved several 
times; the quantity of fat on the other hand, as compared with 
that of older cows, is smaller (Teichert, Hittcher, Hogstrom, Vieth 
and others). 

The variations which are manifested in the production of milk 
during single lactation periods are considerable, and depend en- 
tirely upon the individual, as does the length of the milking period. 

For a few days after parturition a product is secreted which 
has very little in common with milk, and which may be considered 
as a product of glandular inflammation as a result of physiological 
irritation. It corresponds strikingly in its appearance and com- 
position, as well as in the microscopical appearance of its cream 
and sediment with the inflammatory product of the milk gland. 

This product called colosirum is a yellowish or even yellowish-red, slimy fluid, 
with an acid reaction. Corresponding to the increased content of albumen, globulin and 



6(3 Internal Influences on the Character of Milk. 



fat in colostrum, as compared "n-ith ripe milk, the amount of dry substances in eolos- 
tral milk is very high, and its si)ecific gravity is increased. Tiie amount of urea, cre- 
atinin, cholesterin, and lecithin in colostrum is increased. The milk at this stage is 
rich in fat-containing glandular epithelium in the form of foam cells, and seal-ring- 
shaped cells with so-called caps and moons, and in allniminophores. Numerous leuco- 
cytes are to be found, and during the first days red blood corpuscles are also present 
in great numbers. According to Emmerling, cow colostrum, on the ?norning after the 
birth of the calf, consists of 76.14% of water, and 23.86% of dry substance, of which 
4.705% is casein, 0.58 albumen, 8.320 globulin. Compared with normal milk, the fat 
content is increased or diminished, the milk sugar diminished, and the ash contents 
increased. 

Engling found the following values for colostrum : 

Immediately after After 10 After 24 After 48 After 72 

calving hours hours hours hours 

Specific gravity 1.068 1.046 1.043 1.042 1.035 

Solids 26.83 21.23 19.37 14.19 13.36 

Casein 2.65 4.28 4.5 3.25 3.33 

Albumin and globulin 16.56 9.32 6.25 2.31 1.03 

Fat 3.53 4.66 4.75 4.21 4.8 

Milk sugar 3.0 1.42 2.85 3.46 4.1 

Ash 1.18 1.55 1.02 0.96 0.82 

The composition of the ash differs from that of ripe milk, as may be observed 
from the findings of Sehrodt and Hansen : 

Eipe Milk (10 days 
Colostrum after calving) 

KoO 17.4 24.12 

NaoO 10.10 8.72 

CaO 22.99 22.69 

MgO 6.88 2.92 

FeoOs 0.42 Traces 

SO3 2.82 4.10 

P9O5 34.30 30.73 ^ 

"Cl 6.85 8.30 

The ferments in colostrum also deserve special consideration. 
The amylase content is considerably increased, also the amount 
of catalase. During the colostral period the milk further con- 
tains hemolytic amboceptors and increased complement. Formalin 
methylene blue is not decolorized. The reaction of the colostrum 
is acid. 

The colostral period lasts from 3 to 5 days after calving. In 
heifers the transition period results more slowly than in old cows 
(Deisman, Hittcher). Up to the end of this period there is a 
constantly increasing approach to the properties of ripe milk^ 
together with an increase in the yield, which continues to increase 
until the first or second month, and then gradually recedes and 
finally rapidly diminishes towards the end of the lactation period. 
The reduction of the milk yield corresponds with an increase in 
the percentage of fat. The fat globules become smaller and more 
numerous. At the end of the lactation period the milk again 
assumes the character of colostrum, becoming especially rich in 
chlorine, and sodium oxide, while the phosphoric acid and the 
potassium contents appear diminished. The milk becomes salty, 
bitter, and its reaction alkaline. The entire time of lactation or 
one lactation period, usually lies between the birth of two calves^ 



Influence of Disease. 67 



and is divided into the lactation period and the dry period. Good 
milk cows give milk on an average for 300 days. Cows which are 
not bred again, or which cannot be impregnated, may have a con- 
siderably longer lactation period. 

During estrum a considerable diminution of milk in quantity 
and quality may be observed in cows. Sucking calves may at this 
time become affected with digestive disturbances. Hittcher and 
Neumann state that the quantity and the proportion of fat dimin- 
ish, while the casein contents and the specific gravity of the milk 
are increased. There are however no set influences in one and the 
same animal, and still less so in different individuals. Sometimes 
the quantity of milk even increases, and not infrequently the milk 
becomes abnormally rich in fat (Martiny). Fascetti and Bertozzi 
found diminished quantity, increased specific gravity, and in- 
creased dry substance, which they supposed resulted from the in- 
creased proteid contents, especially from the increase of fat. The 
volatile fatty acids in the fat according to Nilsen are diminished, 
and the degree of acidity of the milk is frequently increased (Mez- 
ger). As a whole, however, the milk is not materially changed 
(Weber). 

No observations have been made on the influence of coition 
and the beginning of another pregnancy. However the milk of 
cows far advanced in pregnancy frequently has a lower value. It 
coagulates sometimes as early as in the sixth, seventh, or eighth 
month of the gestation period. Finally it becomes slimy, yellow, 
and shortly before the cow goes dry it shows a similarity to colos- 
trum. The amount of phosphoric acid and lime, contrary to that 
in colostrum immediately after calving, is diminished, and the 
taste is bitter and rancid (Backhaus). 

If cows are spayed 5 to 6 weeks after calving the milk is 
supposed to be richer in fat, casein, and ash. The lactation period 
of such cows is considerably lengthened, according to Grouin ex- 
tending to 6 years. Lajoux on the other hand states that in healthy 
animals the quality of the milk remains the same, but during the 
course of lactation the cows do not dry off so rapidly and the yield 
is therefore greater. 

Milk which is produced after abortion is supposed to be sim- 
ilar to that of ripe milk (Schaffer and Hess). The lactation period 
however is short, and the milk yield small. 

If the cow remains farrow for a long time a greater yield is 
obtained. This however is only slight, and does not compensate for 
the shrinkage during the latter part of the milking period. 

Influence of Diseases. 

Relatively little is known of the chemical changes which 
milk undergoes from the influence of general affections of ani- 
mals. We are in possession of better information relative to the 



58 Internal Influences on the I'liaraoter of I\Iilk. 

occurrence of specific disease agents in milk, and it is known that 
these pass into the milk either directly from the blood being then 
eliminated with the milk, or else they reach the milk through sub- 
sequent contamination of the milk with excretions. 

A rapid diminution of the milk yield is characteristic in all 
acute diseases associated with great pain and fever, and in some 
cases a sudden cessation of the secretion may be observed. 

Whenever the yield of milk of a cow suddenly shows a con- 
siderable diminution, all of her milk should be excluded from mar- 
ket, even though the animal shows no visible affection and before 
the disease can be recognized as a general or specific affection. In 
the sense of the pure food law the milk of every severely affected 
cow should be considered unfit for food without any further con- 
sideration. 

Sometimes this unfitness of the milk is numifestod by strong 
objective perceptible changes, as compared with the secretion of 
healthy animals. 

The milk may become bitter, salty, have an increase of ash and 
albumin, and coagTilate more rapidly than healthy milk (Jensen). 
The fat content of the milk is at the same time diminished or in- 
creased, while the sugar and ash contents may show fluctuation. 
The amount of catalase present, according to Spindler, may in- 
crease considerably, especially in cases of peritonitis and tubercu- 
losis. The reaction of the milk remains acid or becomes slightly 
alkaline. According to Schnorf, most of the internal affections, 
even when the udder is not involved, produce a diminution of 
sugar and proteid contents as a result of increased metabolism. 
The electrical conductivity of the milk of animals with general 
affections is subject to great fluctuations. After tuberculin injec- 
tions with subsequent fever, the milk shows a slight increase in 
its electrical conductivity. The index of refraction in pathological 
milk is normal, and not diminished ; the temperature at which 
freezing occurs is not infrequently higher. 

During the course of individual diseases the following should 
be considered: 

An elimination of toxins and toxic products of metabolism 
with the milk is to be feared in all septic and pyemic diseases. If 
with this there is a possibility of contamination with pathological 
excretions, as for instance in septic metritis, hemorrhagic or 
ichorous enteritis, or in the retention of putrid afterbirth, the milk 
should be considered harmful. In septic metritis the infective 
agents pass from the uterus into the meat and into the udder, from 
which they may be eliminated. Basenau demonstrated the Bacillus 
morlnficans hovis, a meat poisoning organism of the colon typhoid 
group, in the meat during the existence of septic metritis. The 
stapylococci and streptococci which are frequent participants^ in 
mixed infections of the uterus, are also eliminated with the milk, 
provided the udder has not already ceased its secretion. 



Influence of Disease. 69 



Milk from cows affected with acute and sub-acute intestinal 
inflammations should be judged in the same way as milk from 
animals affected with septic metritis. 

The ingestion of milk from cows affected with bloody or fetid 
diarrheas should be especially guarded against. The appearance 
of sickness in man after the ingestion of such milk has been satis- 
factorily proved by Gaffky and Follenius. 

Two assistants and a helper of the Hygienic Institute of Giessen drank milk of 
this character and became sick with dullness, headaches and chills. After two days 
diarrhea, vomiting and high fever appeared. The clinical manifestations in the two 
assistants simulated those of typhoid fever, while in the helper they were similar to 
those of Asiatic cholera. The milk originated from a cow affected with hemorrhagic 
enteritis. Gaffky demonstrated rapidly growing and strongly virulent colon bacilli 
both in the bloody excrements of the cow and in the stools of the affected patients. 

In the presence of infectious diseases the milk of the en- 
tire stable should be withdrawn from use, or should be rendered 
safe by suitable treatment, as for instance by pasteurization. Such 
milk should never be sold as certified or infants' milk. Jensen ex- 
tends this prohibition even to milk from stables in which white 
scour of calves, and other calf affections of an infectious nature 
have occurred. 

Dangerous properties of the milk should also be considered in 
the appearance of other diseases, as for instance malignant catarrh- 
al fever, purulent broncho-pneumonia, traumatic pericarditis, rin- 
derpest, etc. (Bongert). In all cases of hemorrhagic, purulent, 
acute or chronic inflammations of the kidneys the milk should be 
judged similarly to milk from animals with intestinal inflamma- 
tions. In such affections the freezing point of the milk approaches 
zero, and the refraction index is lower. At the same time these 
values in animals affected with inflammations of the kidneys vary 
extensively. 

Special Infectious Diseases. 

Tuberculosis of animals, especially its hygienic importance, 
is considered here in connection with tuberculosis of the udder. 
It should be mentioned at this point that some investigators be- 
lieve that the toxins of the tubercle bacillus pass into the milk. A 
change of the quality of the milk will occur only in cases in which 
the advanced chronic affection of the animal results in lasting 
emaciation, or when an acute attack of the disease, associated with 
fever, appears during the chronic course of the disease. In tuber- 
culosis the milk may become bluish, and poor in fat, the sugar and 
proteid substances may be diminished, or the latter may be even in- 
creased (Storch). Several tables, which indicate the experimental 
results of Monvoisin, are taken from Grimmer 's ''Chemistry and 
Physiology of Milk." 



"Q Tnternal Influcnoes on the CliaracttT of Milk. 



1000 gm. of milk coiitainod Tube.vuiou. o..ws Avitiiout 

Healthy cows tuhorculosis of the udder. 

Acidit V as lactic acid 1 . 543 . OG-t 1 . 292 

Totarnitrogeii 5.87 8.67 4.21 

Fat 46.5 29.6 59.7 

Sugar 43.5 29.8 43.9 

Solids 142.3 126.05 147.5 

Ash 7.3 8.2 6.7 

Clilorin (sodium chloride) ... 1.4 4.13 1.05 

Freezing Point — .55 — — 

Eef raction at 15 deg 1 . 3434 1 . 3416 1 . 3442 

In rinderpest;, according to Busson, the amount of fat and 
sugar diminished rapidly, whereas the casein, albumin and salt 
increased. The passage of the contagion of rinderpest into the 
milk in a direct way from the blood is j^robable; the milk, how- 
ever, can be contaminated with certainty through infectious secre- 
tions and excretions. Rinderpest is of no practical importance 
from the standpoint of milk hygiene, to most of the European 
countries (with the exception of Turkey), since it has been eradi- 
cated with the aid of veterinary police measures and even in the 
event of any possible introduction, it Avill be immediately sup- 
pressed. 

Milk from cows affected with contagious pleuro-pneumonia 
is supposed to have caused the death of children (Randou, Lecujer 
and Wiedemann). Secretion of milk is immediately reduced at the 
onset of this disease, it becomes poor in fat and sugar, richer in 
albumin and ash, its appearance resembles that of colostrum, and 
its taste is peculiar. The contagion of pleuro-pneumonia appears 
to pass into the blood but rarely, and therefore its elimination in 
the milk can occur only exceptionally, if at all. Contagious pleuro- 
pneumonia is also subject to the most stringent veterinary police 
measures, and therefore has but little practical imjoortance for 
milk hygiene. 

Similar conditions prevail with pox of cattle. This disease 
however demands our interest for the reason that the infectious 
agent of cow pox must be considered as a mild form of smallpox 
of man. Cattle usually become affected through transmission of 
the disease from naturally infected men, or from those vaccinated 
with cow pox. The infection occurs if during milking the contagion 
of pox is rubbed into visible or invisil^le wounds of the skin of the 
udder. The infected teats manifest roundish or oval, hard papules 
of the size of a pea, which after 1 to 2 days change into yellowish- 
Avhite vesicles of a mother-of-pearl luster. After ripening into pns- 
tules which requires from 8 to 10 days, the lesions show a charac- 
teristic depression in their center, the so-called navel of the pox. 
They either rupture and suppnrate, or dry and heal, leaving a 
superficial scar. 

The udder becomes sensitive to pain, the milk is thinner, and 



Influence of Disease. 71 



of lower specific gravity, but richer in albumin (Jensen). The 
injection of the contagion of pox into the ducts of the udder results 
in the development of pox vesicles on the walls of the milk ducts. 
After 2 to 3 days a swelling of the udder, with increased sensitive- 
ness, develops and the secretion is changed. It becomes purulent 
and bloody on the eighth to the tenth day (Lienaux and Hebrant). 
Transmission from animal to animal may be brought about 
by milking, and the entire herd in a stable may rapidly become af- 
fected. The course of cow pox is usually benign. According to 
Herz the milk becomes rich in cells, contains colostral bodies, and 
it has an unpleasant taste. Careful examination showed the fol- 
lowing results : 

Beginning of After 13 After 40 

observations days days 

Specific gravity of the milk 1 . 0265 1 . 0270 1.0215 

Specific gravity of the whey 1 . 0245 1 . 0235 1 . 0209 

Acidity according to Soxlilet-Henkel . 5.3 6.6 4.1 

Fat 5.36% 4.02% 5.54% 

Solids 13.31 11.82 12.25 

Fat-free solids 7.95 8.81 6.72 

Ash 0.72 0.72 0.8 

Transmission of pox from cattle to man is of course very 
readily possible, and is not at all uncommon as a result of milking 
affected animals. After the ingestion of infected raw milk the pox 
exanthema may develop on the face (Jensen). 

The so-called false or gangrenous variola which may be fre- 
quently observed on the teats of fine-skinned, fresh milking animals 
should not be mistaken for true pox. These eruptions are pro- 
duced by the ordinary pus-producing organisms, which have been 
rubbed into the skin during milking or have penetrated the skin 
by means of various injuries. Small furuncles and skin abscesses 
result, which heal without influencing the formation or secretion 
of the milk. Healing is of course retarded through the act of milk- 
ing, and during the presence of the pus cells, blood and pyogenic 
organisms may pass into the liiilk in small quantities. These false 
pox lesions are not very important. 

Of much greater importance than cow pox is foot-and-mouth 
disease which sometimes appears extensively. This is a highly 
acute febrile disease which is transmitted to cloven-footed animals 
with remarkable ease. The most striking symptom which occurs 
in association Avith the disease, the vesicular eruptions, may also 
affect the udder, and especially the teats. 

The udder swells, becomes painful, and red-bordered vesicles 
develop in sizes up to that of a walnut, which burst during milking 
or spontaneously, leaving painful ulcers. During the beginning 
of foot-and-mouth disease the yield of milk is considerably dimin- 
ished, sometimes one-quarter less than the usual yield, as a result 



72 Ttitcnial Influences on the Character of Milk. 

of tlie febrile affection and on account of the inappetence due to 
the pain caused by the vesicles in the mouth and on the feet. The 
effect of the disease upon milk secretion varies according to the 
individuals, the age and the lactation. Siedamgrotzla-^, Weber 
and Born have published the effects of the disease on milk secre- 
tion during outbreaks in certain herds. In 43 cows the quantity 
of milk at the height of the disease dropped from 745 to 364 liters, 
and again rose after the eradication of the outbreak to 522 liters. 
Thirty cows of another herd gave only 30 liters instead of 300 
liters of milk during a period of eight days. In a third herd the 
quantity of milk dropped from 510 to 260 liters, later rising to only 
350 liters. Other figures showed a decrease from 750 to 280 liters, 
with a subsequent rise to 400. The diminished yield per cow per 
day Avas from 5 to 6 liters and even more. In cows that have been 
milking for a long time the loss in milk reaches as high as 75%, 
in animals in the middle of the lactation period up to 43%, while 
in fresh milkers it may amount to 55% (Hutyra and Marek). 
Sugar and fat contents diminish, but at times the amount of fat 
may become considerably higher. The volatile fatty acids are 
diminished, but the milk contains more albumin and salts, an in- 
creased amount of throAvn-off epithelium, colostral cells, pus cells, 
and also red blood corpuscles (Lavena, Kalantar, Herberger, 
Kreis, Vogler and others). The catalase content is increased even 
if the udder manifests no changes (Bertin-Sans and Gaujoux). 

Honigiiiund examined five cows affected with foot-and-mouth 
disease, one of which was not visibly affected on the day of the 
examination although already infected. The individual data in- 
side of nine davs were as follows : 



Quantity 




Tempera- 


Specific 


Fat Con- 


Nitrogen- 








of INIilk 




ture 


Gravity 


tents 


ous Subs. 


Sugar 


Solids 


Ash 


15 


L. 


38.7 


1.032 


3.05 


2.99 


4.24 


11.62 


0.74 


6—7 




39.6 


1.031 


5.4 


2.97 


3.63 


13.00 


0.63 


6—7 




38.9 


1.030 


4.3 


2.99 


3.80 


12.81 


0.89 


about 8 




39.0 


1.030 


3.43 


3.04 


3.91 


11.33 


0.65 


8 — 10 




38.6 


1.031 


3.06 


3.04 


4.15 


11.01 


0.70 


8 — 10 




38.4 


1.029 


2.9 


3.1 


4.49 


12.03 


0.69 


about 10 




38.6 


1.030 


2.84 


3.19 


4.57 


11.21 


0.71 


10 — 11 




38.5 


1.032 


3.45 


3.24 


4.41 


11.77 


0.67 


about 12 




38.4 


1.031 


3.25 


3.33 


4.38 


12.30 


0.70 



It appears also from the other investigations of Honigmund, 
in which the animals showed s^niiptoms of the disease as early as 
on the first day of the examination, that the fat and ash content 
is greater in the first day than in normal conditions. The total 
solids and also the fat-free solids fluctuate considerably. 

When catarrh of the milk ducts becomes associated with foot- 
and-mouth disease, the milk becomes yellowish, of a rancid, bitter 
taste, colostrum-like, and similar to the secretion during other in- 



Foot-and-Mouth Disease. 73 



flammatory conditions of the udder, that is, slimy, watery and in- 
termixed with coagulum. ' 

It is an important fact that milk from animals which are af- 
fected with foot-and-mouth disease will contain the virus of foot- 
and-mouth disease, if it has been contaminated by the vesicular 
contents. Nocard succeeded in proving, however, by careful ster- 
ile drawing of the milk from cows affected with foot-and-mouth 
disease, that the milk does not contain the virus of foot-and-mouth 
disease as it leaves the udder. 

Nevertheless it is not satisfactorily proved that a direct 
elimination of the virus may not take place at the beginning of the 
febrile state, as at this time the virus is present in the blood If 
the udder itself is affected by the eruptions of foot-and-mouth 
disease it is hardly possible to avoid contamination of the milk with 
the vesicular contents. Considering the ease with which the virus 
of the disease is spread, it may be assumed that the entire milk of 
a herd affected by the disease, under ordinary conditions of milk 
production, contains the contagion of foot-and-mouth disease, 
strict veterinary pohce measures must be inaugurated to prevent 
the spread of the disease. Sale of the milk should be permitted 
"^Tl^^. ?y^^^^^* heating. The maintenance of a temperature 
K,-^^' one-half hour will make the milk perfectlv safe 

Milk containing the living virus of foot-and-mouth disease 
must be considered deleterious to human health, since it has been 
estabhshed by experiments and observations that the disease is 
transmissible to human beings. Vesicular and ulcerated inflam- 
matory changes of the buccal mucous membrane with fever and 
general symptoms develop with possible vesicles and ulcers on the 
hands, arms, breast, lips, ears, and in the throat. Vomiting and 
diarrhea may be associated with symptoms of a gastro-intestinal 
mtlammation, and the affection may even terminate in death (Bus- 
senius and Siegel, Jensen, annual reports of the Imperial Board 
ot Health, Hertwig, Stickler, Schreyer, Krajewski, Walkowski, and 
others). Bongert suggests the separation in dairy stables of the 
non-altected, slightly and severely affected animals into isolated 
groups and m order to reduce the economic losses as low as pos- 
sible the milk of these groups should be treated in different wavs 
Heated milk from the non-affected animals for instance, could be 
utilized as infant's milk. The milk from slightly affected animals 
could be marketed as ordinary milk [after pasteurization], while 
the milk from the severely affected cows or milk changed in its 
consistence, should be excluded from consumption even in a heated 
condition. Even with this separation the losses will necessarilv be 
high as a result of the enforcement of stringent sanitary regu- 
lations. .' to 

According to Ebert sour milk 3 to 4 davs old is no longer 
capable of transmitting the infection. The transmission is possi- 



74 Effect of Internal Influences. 



ble through cheese and butter (Frohner, Ebstein, Thiele, Schnei- 
der, Frick, Frohlicli). 

The general rules which have been indicated above obtain also 
in changes of the milk in malignant oedema, blackleg, or parturient 
blackleg of cattle. Transmission of these diseases through the 
consumption of milk from affected cattle, or through the diseased 
products of contaminated milk, is not to be feared; besides milk 
production ceases very rapidly in the affected animals. 

The same rules should apply in judging milk from animals 
affected mth hemorrhagic septicemia, a disease which is pro- 
duced by a bi-polar bacterium. This disease is transmissible to 
calves, through sucking or feeding milk from affected animals. 

Anthrax of cattle should also be mentioned. This runs in an 
acute or sub-acute form, and as a rule is associated with a sudden 
cessation of the milk secretion, which occurs even as early as at 
the beginning of the fever. The anthrax bacilli only multiply 
towards the end of the disease sufficiently to cause a direct passage 
from the blood into the milk. If the secretion has continued to 
some extent this direct passage is possible even if no hemorrhages, 
such as are typical during the course of anthrax, have developed 
in the parench^ana of the udder. The demonstration of anthrax 
bacilli in milk has been accomplished microscopically, and by 
inoculation and cultural experiments, but not in all the cases 
which have been examined (Bollinger, Chambrellent and Mous- 
sou, Feser, Monatzkow). 

In severe cases the milk becomes yellowish, bloody and slimy. 
At the appearance of the fever the fat and sugar contents are in- 
creased, while the proteid contents are diminished. 

The danger of infection through the ingestion of raw milk con- 
taining bacilli is slight, since the anthrax bacilli are digested by 
the gastric juice. More dangerous than the bacilli which may pass 
into the milk from the blood are the anthrax spores which may 
reach the milk through contamination with manure of affected 
animals, or through straw and stable dust, since the resistant 
spores are not destroyed by the gastric digestion. The virus may 
also be present at times in normally healthy animals after they 
ingest food containing anthrax spores.. The milk may become 
infective through contamination with feces from such bacilli car- 
riers. In spite of the fact that there are remarkably frequent 
opportunities to obtain milk with bacilli and spores from localities 
in which anthrax persists epizootically as a disease of the soil, yet 
only one anthrax infection of man is known to have occurred 
through the ingestion of milk. This resulted in a patient with 
typhoid fever, who after drinking li/o liters of milk became affected 
with intestinal anthrax. The milk was derived from a cow mth 
a malignant pustule on the udder, which had died in the meantime 
from anthrax. 



Rabies. 75 

Lehnert states that the calf of a cow affected with anthrax re- 
mains well, although it may suck the mother through the entire 
course of the disease. 

Even though milk offers a splendid nutritive medium for 
the anthrax bacillus, an increase of bacilli only occurs during the 
first three hours. Keeping the milk at room temperature for 18 to 
24 hours, is followed by the death of the bacilli (Caro). At the 
beginning of souring the vegetative forms of the virus are quickly 
destroyed; the spores however remain active (Inghilleri). If 
anthrax bacilli are cultivated in milk, coagulation occurs under the 
rennet action of the peptonizing bacterial ferments. The coagulum 
again slowly dissolves, and the milk separates into fat and whey. 

Less important than anthrax is rabies, as this disease occurs 
much more rarely in cows. According to Nocard and Bardach 
the milk of animals affected with rabies contains the virus. Never- 
theless the danger to man from the ingestion of such milk is hardly 
probable, since it is impossible to affect experiment animals by 
feeding fresh milk (exceptions are rats and mice). A nursing 
infant of a woman affected with rabies remained well, although 
it was fed with the milk of the patient until one day before her 
death (Bardach). The uninjured mucous membrane of the mouth, 
pharynx, and the intestinal tract does not offer opportunity for 
infection. This opportunity is afforded only when destruction of 
tissue and small wounds permit the entrance of the contagion. 
Thus for instance Galtier succeeded in producing rabies through 
rubbing brain material of rabid animals into the mucous mem- 
brane of rabbits. According to the observations of Virschikowsky 
the rabid virus is destroyed by the gastric juice. 

Very little, or nothing at all is known relative to the special 
relationship of other infectious diseases to milk, as for instance 
malignant catarrhal fever, croup of cattle, the blood diseases of 
cattle caused by spirochsetes, trypanosomes and piroplasma, or in- 
fectious vaginal catarrh and infectious abortion. In the presence 
of infectious vaginal catarrh and contagious abortion the milk 
secretion is supposed to be diminished. 

It should be remembered that in such affections the passing 
of the disease agents from the blood into the milk is possible. 
[That the bacillus of infectious abortion is eliminated by the milk 
has been definitely established. See Bureau of Animal Industry 
Circular No. 216]'. 

In a case of icterus in a woman Mayer observed the passage 
of bile acids, especially taurocholic acid into her milk. 

Finally two other diseases should be mentioned which ma3^ 
be transmitted from animal to man : 

1. Milk Sickness. A rather peculiar disease, called ''milk 
sickness," is found in the central part of the United States, where 
it at times occurs as an epidemic among cattle and people. In 
cattle, the first indication of disease is dullness, followed by violent 



Effect of Internal IiiHiii'nces. 



trembling and great weakness, wliieli increases during the suc- 
ceeding day until the animal becomes paralyzed and dies. Through 
the ingestion of flesh, milk, or dairy products of an alfected animal 
the disease is transmitted to man or to another animal, and at- 
tacks produced in this way most frequently prove fatal. In man 
the disease develops with marked weariness, vomiting, retching, 
and insatiable thirst. Respirations become labored, peristalsis 
ceases, the temperature is subnormal, and the patient becomes 
apathetic. Paralysis gradually follows and death takes place 
quietly without rigor mortis. 

Many efforts have been made to elucidate the question re- 
garding the nature and cause of this disease, but although many 
theories have been discussed none of them has so far been general- 
ly accepted. Some investigators hold that the disease is of micro- 
organismal origin, some that it is due to auto-intoxication, while 
others think it is caused by vegetable or mineral poisons All 
seem to agree, however, that the disease is limited to low, swampy, 
uncultivated land, and that the area of the places where it occurs 
is often restricted to one or a few acres. Furthermore, when such 
land or pastures have been cultivated and drained the disease dis- 
appears completely. 

The discovery of a new focns of this disease in the Pecos Val- 
ley of New Mexico in November, 1907, gave Jordan and Harris the 
opportunity of studying this peculiar affection by modern bacter- 
iological methods. As a result they have succeeded in isolating 
in pure cultures from the blood and organs of animals dead of 
this disease a spore-forming bacillus which they name '' Bacillus 
lactimorhi." With this bacillus they have reproduced in experi- 
ment animals the symptoms and lesions peculiar to milk sickness 
or treml^les, and from these animals the same organism has been 
recovered in purit}^ It therefore appears to have been demon- 
strated that the bacillus in question is the probable cause of the 
disease. As Jordan and Harris have already indicated, more com- 
prehensive studies, based on a larger supply of material, are 
desirable in order that the many obscure and mystifying features 
connected with the etiology of this rapidly disappearing disease 
may be elucidated. 

From the above facts it seems evident that milk sickness is an 
infectious disease communicable to man, and the cattle owners 
should therefore not be permitted to make use of the meat or milk 
of affected animals for human consumption. Trans.] 

2. Malta Fever. On the coast of the Mediterranean, in South 
Africa, India, China, Philippines, America, and especially on the 
Island of Malta, there occurs in goats a disease which exists in 
the animals without producing any or at most only very slight 
sjnuptoms. Cows may also possibly be affected. The infected 
animals eliminate for months, frequently at intermittent periods, 
the virus of the disease (Micrococcus melitensis , Bruce). Follow- 



Mastitis. 



77 



ing the ingestion of such milk ' ' Malta Fever ' ' develops in man. It 
has a protracted course with recurrences, and is accompanied by 
anemia, headaches, rheumatic pains, constipation and swelling of 
the joints. Malta fever terminates fatally in about 3% of the 
cases. The goats show on postmortem, swelling of the spleen 
and lymph glands, frequently also inflammations of the kidneys 
and lobular pneumonia. The virus is relatively resistant against 
souring of the milk, but at 70 deg. C. it dies in 10 minutes. 

According to Zammit about 10% of all the goats on the Island 
of Malta eliminate the virus, while 50% of the animals show by 
the agglutination test that they are or have been under the influ- 
ence of the Micrococcus melitensis. 

We are in possession of better information concerning the 
changes which milk undergoes in inflammations of the udder than 
we have regarding the effect on the milk secretion as a result of 
general diseases, or regarding the importance of milk from affected 
animals from a hygienic standpoint. 

Changes in Appearance, Consistence, Contents, Etc., During- an 

Attack of Mastitis. 

Relatively very little is known as to the influence of the dis- 
eases ot the udder on the chemical and physical character of the 
milk, although it is well known that with the changes in function 
and condition of the organ the product is also changed, as com- 
pared with the product of the normal gland. Even in the same 
disease the product varies in accordance with the intensity dura- 
tion and the extension of the disease, the same as it naturallv 
varies m accordance with the nature of the injury to which the 
parenchyma is subjected. As a result of these conditions the re- 
sults o± the data of different authors vary considerably 

It may be said in general that in affections of the udder the 
projDortion of the proteids, sugar, salt, fat, and enzvmes in the 
milk becomes altered and that the relation of the individual pro- 
teids, the salts and the enzymes, also undergoes fluctuations. In 
acute and greatly extended chronic inflammations, both fluid and 
cellular constituents of the blood may pass into the milk, cells of 
the parenchyma are thrown off, coagulation sets in, and brieflv, 
the milk changes more or less rapidly in appearance, taste and 
contents, so that it deviates considerablv from the milk of healthv 
cows. ' ^ ^J 

At times none of these characteristics appears, especially in 
the early stages of chronic inflammations of the udder, or after 
the subsidence of the acute symptoms, and it is then onlv possible 
with tlie aid of certain methods of examination to differentiate 
such altected milk from normal. 

Therefore of special importance to milk hygiene are the 
chronic inflammations, and inflammatory stages in which the 



78 Effect of Internal Influences. 

clianges of the secretion appear slowly, and relatively late, while 
inflammations of an acute character very quickly produce a tre- 
mendous change in the secretion, the mixing of which with market 
milk would be the grossest negligence. It is to be regretted that 
such cases occur. 

Appearance of affected milk : In forms of inflammation which 
are associated with rapid development, painful swelling and in- 
creasetl temperature of the udder, the milk nsually has a bloody 
discoloration, later becoming yellow (colostrum-like), and finally 
changes into a custard, or honey-like secretion, in which thick, 
yellow and yellowish-brown flakes are suspended in a more or less 
clear serum or plasma. 

Such changes are observed in samples of milk in acute forms 
of mastitis, through infection of bacteria of the colon group, in 
mixed infections, in acute attacks or in great extension of strep- 
tococcic mastitis, and in infections with the Bacillus pyogenes, etc. 

In chronic affections the milk clianges only slightly or not at 
all during the beg-inning of the disease, or it may appear normal 
long before the disease as such is considered cured. If such nor- 
mal appearing milk from affected quarters is allowed to stand 
for several hours a white, yellowish-white or yellowish sediment 
settles to the bottom. At the same time the quantity of cream is 
increased and changed, appearing yellowish, tenacious, and when 
shaken it assumes a cloudy or wavy appearance. If the migration 
of the pns corpuscles from the blood vessels becomes more inten- 
sive the milk appears thick, ^'-ellowish, cream-like, and after stand- 
ing separates into a yellowish-white to ocher colored sediment, 
which may amount to two-thirds or more of the entire mass, and 
into a dark, transparent, yellowish-grey to greenish-yellow skim 
milk. The sediment layer is at times increased, at other times 
decreased. The cream becomes granular, shredded, and tenacions. 
If red blood corpnscles are eliminated in great numbers they col- 
lect in the form of a red disc on the yellow to yellowish-brown base, 
which is composed of leucocytes and coagulation masses. In 
hemorrhagic stages of the inflammation the milk is pinkish or 
brownish-red; by sedimentation it separates into a Bordeanx-red 
or rust-colored precipitate, and a pinkish-red layer of cream over 
the reddish-gray skim milk. 

In other cases the milk becomes grayish and watery, and only 
a few thin conglomerates and fat globules indicate the layer of 
cream. 

Cream and sediment are especially rich in cells in all forms 
of inflammation. Epithelial cells are desquamated into such milk 
in the form of colostral cells, or entire epithelial bands, and numer- 
ous polynuclear leucocytes, besides single epithelial cells, into 
which macrocytes penetrate (albuminophores), erythrocytes, cell 
debris, fragments of nuclei, as well as Nissen's globules are found. 

Besides concrements of the most varied quality, casein and 



Mastitis. 79 

fibrinous flakes appear (Zscliokke, de Bruin, Kitt, Sven Wall, 
Doane, Russell and Hoffman, Rulnn, Ernst, Balir and others). 

The taste of milk from affected quarters of the udder is also 
affected markedly, the milk becoming salty, bitter, and pungent. 
According to Craandijk in 67% of cases the taste of the milk 
changes in streptococcic mastitis. 

From the appearance which the affected quarter manifests, 
as compared with healthy quarters, from the change in the behav- 
iour of the animal, from the varying quantity of the secretion 
against the quantity from healthy quarters or the previous yield 
of the same quarter, the milker becomes suspicious of the existence 
of an abnormal condition in the suspected quarter, and the tasting 
test reveals a salty, bitter taste which assures him of the appear- 
ance of a change in the activity of the gland. If the udder secre- 
tion could be examined on the hollow of the hand before being 
milked into the pail, in order to determine the possible presence 
of flakes, etc., as should be the duty of the milkers, then the mix- 
ing of such mill! from affected quarters would not occur to the 
extent that it does at present, as has been proved on numerous 
occasions. A great deal would be gained if the milk from those 
quarters which produce a milk so changed that its abnormalities 
can be recognized by its appearance or taste could be totally de- 
stroyed. As a matter of fact milkers can much more readily rec- 
ognize developing inflammations of the udder (as for instance 
streptococcic mastitis) from the varying conditions of the udder, or 
quarter, the quantity of milk, and the behavior of the animal, than 
the veterinarian can by a single clinical examination. Therefore the 
method applied in practice consisting of a single clinical examina- 
tion of the cows producing infant milk at the time of purchase, or 
every 3 to 4 weeks is not sufficient to determine the presence of ud- 
der affections. Periodical examinations of all cows producing certi- 
fied milk, supplemented by tests of the milk obtained at the time of 
the examination, are necessary when the inspection is to serve its 
purpose. 

At the examination in the stable a comprehensive history 
should be taken from the milkers relative to the general condition 
of the cows, their action during milking, the condition of the teats 
and the gland tissue, the inflammatory changes noted, in fact all 
points which may offer valuable supplements to physical examina- 
tion. One may learn from questioning that the cow milks very 
hard from one quarter, that she sometimes refuses to ''give down'"' 
her milk, or that she "draws up" the milk or that recently the 
cow has shown a tendency to kick during milking. At other times 
one may hear that the parenchyma contains knobs or lumps or that 
the teats contain beads or warts, or are ''fleshy," the quantity 
of milk is diminished, the milk is sometimes hot, "heated," or 
that the cow has the "cold garget" Avithout any inflammatory 
indications of streptococcic infections. The milk is ropy, the 



80 Eii'cft oi: lulenuil iullueiicc- 



quarter is ''blind," tlie milk contains stringy clots and other 
tilings. 

The keeping of milk records and the taking of milk samples 
at least every four weeks, should be reqnired of all owners of 
animals which ])rodnce milk for city consnmption and those fur- 
nishing it to wholesale milk dealers. 

Together with the visible changes in the milk, changes of the 
value of the chemical and physical properties occur which have 
been especially studied by Guillebeau and Hess, Schaffer and 
Bondzynski, E. Seel, Mezger, Fuchs and Jesser and Mai and 
Ixothenfusser, 

These changes in the contents and properties are therefore 
especially important since frequently values are obtained which 
suggest adulteration with water. Irreproachable comparative tests 
of milk obtained directly from the stal)le may indicate however 
that in the specific cases the investigations M^ere l)eing made Avitli 
al)nornial milk. 

According to Schaflfer and Bondzynski 's examinations tlio milk from cows affected 
with mastitis showed the following values : 

Water Solids. Fat Pro- Milk Total % % 

teid Sugar Ash P0O4 CI. 
In non-infectious 

garget 92.83 7.17 0.82 4.01 0..53 0.79 7.3.5 35.76 

In yellow gait 89.34 10.66 1.99 6.00 1.84 0.83 

In parenchymatous 

mastitis 90.26 9.74 2.16 4.21 1.01 0.97 19.21 27.79 

In comparison with healthv 

milk 87.75 12.25 3.4 3.5 4.6 0.75 20.0 14.0 

The milk sugar content was also considerably diminished; the amount of mineral 
substances on the other hand was increased. Guillebeau and Hess give the following 
values in milk from cows with affected udders: 

Duration of the Disease and Origin 
of the Milk 



Specific 


Solids. 


Fat 


Nitrog- 


Milk 


Ash 


Gravity 






enous 
subst. 


Sugar 






7.45 


0.52 


6.17 




0.85 




5.15 


0.22 


4.26 


0. 


0.82 




9.80 


1.95 


2.98 


4.06 


0.81 


1.0314 


11.28 


2.72 


3.50 


4.35 


0.70 




7.69 


1.09 


5.74 


0. 


0.87 




23.58 


9.30 


8.53 


4.68 


1.07 




1.5.88 


4.50 


5.37 


5.14 


0.87 




9.66 


2.09 
0.53 


6.74 
5.13 


2.09 


0.85 




1.5.88 


4.50 


5.37 


5.14 


0.87 


1.0430 


20.94 


0.97 


16.65 


2.61 


0.71 


1.0379 


18.18 


2.80 


7.93 


2.04 


0.91 



11/2 clays 

2 (i 

5 " udder recovering 

7 " 

2 " 

2 " 

11/^ ' ' from two affected quarters 

ly. " from two affected quarters 

1 " 

8 ' ' from two affected quarters 

2 ' ' from two affected quarters 
21 " 

In most ca.=es the specific gravity is lower (Seel, Mezger, Fuchs and Jesser) and 
approaches the normal only towards the end of the disease. In mixed milk from all 
four quarters the specific gravity is less influenced. 

The quantity of fat, according to Seel, and in some cases of Mezger, Fuchs and 
Jesser, is very much reduced. The latter authors emphasize the fluctuation of the fat 
in sudden jumps. The experience of the official milk control station in Munich also 
gives similar results, at the beginning of the affection frequently finding abnormally 
high or again abnormally low fat contents of the milk. 



Mastitis. 



81 



The amount of milk sugar as a rule is reduced, and rises only with the appearance 
or recovery. ^ ^ 

The solids are likewise usually diminished ; the fat-free substance is also, and only 
becomes increased after signs of recovery have been noticed. 

The amount of proteid coagulable by heat frequently increases enormously, as 
compared with the contents of casein which diminishes. 

The ash content on the average is increased. Eelative to the composition of 
theash the data appear to be contradictory. Although Seel found in 15 cases out of 18 
a diminution of chlorides against an increased quantity of P2O5 Mezger, Fuchs and Jesser 
observed an increase of the chlorine content and a diminution of the phosphoric acid, 
while Steinegger and Allemann found that the amount of P0O5, CaO, K9O and Mo-Q 
diminishes, m general, while the quantity of CI., NooO and SO3 increases. According to 
Hashimoto the ash of abnormal milk closely approaches the ash of blood serum (0.78%), 
consisting of 8.9863 K2O; 36.544 NasO; 7.44 CaO: 1.738 MgO: 17.380 PoO. and 
33.627% CI. ^ 

The reaction of affected milk is mostly alkaline (Seel, Mezger, Fuchs and Jesser, 
Hoyberg, Auzinger, Ernst), or more rarely acid (Zschokke, Henkel, Wyssmann and 
Peter, Ernst). The determination of acidity is recommended by Plant as a means for 
the diagnosis of udder affections. 

Independently from the degree of acidity, the coagulability on the addition of 
alcohol is frequently considerably increased but not always, and in some cases not con- 
stantly. (Henkel, Eullinann and Trommsdorff, Auzinger). 

The refractability of the calcium chloride serum not infrequently suffers con- 
siderable changes upward and downward. Eipper, Ertel, Mairhofer, Schnorf, Mai and 
Eothenfusster, Henkel, Mezger, Fuchs and Jesser found considerable changes in this 
respect and proved that the daily variations in the refraction may be very great in milk 
of individual quarters, and even in the full milk of an animal. Frequently however the 
refraction of the calcium chloride serurn shows no change when compared with the 
milk of healthy animals. 

The same variation obtains in the lowering of the freezing point of milk from 
affected quarters; the values may be considerably higher than that of healthy milk, 
or on the other hand they may be lower. More frequently a high value is observed 
(Schorf, Quiraud and Laserre, Crispo, Bertozzi, Pins). According to Schnorf the elec- 
trical conductivity is always increased, never normal or lower. According to Bonnema 
the increase of chlorides results in an increase of the electrical conductivity. 

A change in the contents of original ferments appears very 
early during the affection, together with an increase of cellular 
elements, especially leucocytes (Zschokke, Bergey, Trommsdorff 
and Rullmann), and fibrinous flakes (Doane, Eussell and 
Hoffmann). 

According to Koning the increase of the catalase content in 
freshly obtained milk is an indication of the affection of the ud- 
der, provided the colostral period has passed. The publications 
of Spindlers and Rullmann (who were enabled to obtain asepti- 
cally milked samples with which to work) and the author's obser- 
vations confirm Koning 's findings. The author observed that in 
slight, local affections of a chronic nature, without febrile mani- 
festations, the content of catalase usually runs parallel with the cell 
content, and it rises when there is an especiallv marked throwino- 
off of epithelia (presence of typical colostral cells). * 

The faculty of splitting up added starch solution likewise in- 
creases m milk from affected udders as compared with that from 
healthy udders. There are no observations relative to the quanti- 
tative effects of peroxydase. According to Weichel the peroxy- 
dase content of affected milk from an artlfically affected goat dis- 
appeared, whereas the healthy milk gave the guaiac reaction 



^2 Effect ul internal Intlueuces. 



The reaction again appeared when the secretion became of a milk- 
like consistency. 

Al'lected milk behaves in various ways on the application 
of f ormalin-methylene blue solution ; frequently a very rapid decol- 
oration of JSchardinger's reagent may be observed (Rulimann, Sas- 
scnhagen, Eievel). iSometimes in typically changed samples the 
reduction does not take place (author's observation). 

As the above-mentioned enzymes (not amylase), at least in 
part may appear to be brought on by bacterial action, their abnor- 
mal presence in milk has a diagnostic importance only in freshly 
milked samples. The case is different wdtli the complement con- 
tent. As indicated in the chapter on antigens, blood constituents 
pass directly into the milk during periods of physiological and 
pathological irritations. Therefore in mastitis, as proved bv 
Bauer and Sassenhagen, complements are demonstrable in the 
milk. This, according to Sassenhagen, is possible even in affec- 
tions in which the Trommsdorff value of the centrifugalized cells 
per 1000 parts of milk is still remarkably slight. 

The alkaline reaction of affected milk, the altered proportions 
of mineral salts, at times the passing into the milk of l)loody parti- 
cles, and the diminution of casein, reduce the coagulability of the 
milk towards added rennet. Affected milk therefore generally 
utilizes a considerably larger quantity of rennet than normal milk 
before it becomes coagulated (Schern). 

The spontaneous coagulation of affected milk also appears to 
be considerably delayed. 

Infectious Agents of Mastitis. 

Nocard and Mollereau, Kitt, Lucet, Bang, Guillebeau and 
Hess, Zschokke, Jensen, Streit, Glage and Sven Wall have offered 
sufficient information regarding the infectious agents of the dif- 
ferent forms of mastitis. 

Most cases of mastitis are produced by streptococci; they 
consist of chronic inflammations of one or more quarters of the ud- 
der. The disease is of relatively small influence on the general 
condition of the animal. 

Bacilli of the coli-aerogenes-paratyphus-paracolon groups pro- 
duce highly acute, parench^nmatous lesions. The general condition 
is severely influenced through infections by bacteria of the 
paratyphus-B group. Locally a gangrenous, septic mastitis de- 
velops with this infection, and the milk is markedly ichorous, 
while in colon infections the secretion is of a sermn-like character 
(Weichel). 

A third form of inflammation of the udder, also of a chronic 
nature, is produced by a representative of the group of the 
BacUhis pyogenes, Sven Wall's pyobacillosis of the udder. The 
Bacillus pyogenes colonizes with a special predilection in the pres- 



Streptococcic Mastitis. go 

eiice of streptococci or staphylococci, and in these mixed infections 
causes severe necrotic inflammations of the udder, and may con- 
tinue to produce chronic mastitis in the atfected udder tissue after 
the disappearance of the other bacteria. 

Other forms of mastitis are produced by tuberculosis and 
actinomycosis, and they usually result through emboli of the in- 
tective agents. _ They may be of a traumatic origin ( actinomycosis ) 
induced by irritation with particles of straw, or barley beard« 
+1 ^^^i^^lie^iore all possible infective agents, as for* instance 
^^;j • 1 "^ ^/ecrop/?orH5, may be found in inflammations of the 
udder, either independently or as mixed infections. 

Only the more important infections of the parenchyma will 
be described here. 

Streptococcic Mastitis. 

. By far the most widely spread type is the streptococcic mas- 
tisis, described by Sven Wall as streptomycosis of the udder 

1 he works of Berg^ey, Craandijk, Trommsdorff and Rullmann, 
Kunze Russell and Hoffmann, Savage, Riihm, and Ernst give gen- 
eral nifoiTnation on this condition. The disease is either sporadic 
or epizootic among the animals of a stable according to the stable 
conditions Ihe disease may attain an especially wide distribu- 
tion when the secreiion of the affected quarter is milked upon the 
floor or into the bedding, and the milkers fail to wash their hands, 
both bad practices which, it is to be regretted, are quite common. 

Zschokke Jensen, Bang, and Sven Wall proved experi- 
mentally that bacteria injected into the cistern penetrate even into 
the farthest alveoli m from 2 to 24 hours. 

^ By inoculating with strains of streptococci of different ori- 
gin varying reactions may be produced in the udder (Bang- ^^re«- 
tococciequi^^i^dStrejtococci agalactice; Gminder: streptococci of 
the stable air and of infectious vaginal catarrh). The manifesta- 
tions also vary after the injection of individual strains into the 
same animals, and from injections of the same strain into various 
animals. In other words the course of the disease varies in ac- 
cordance with the virulence of the organism, the resistance 
-L" ^'""a^ '.f lie extent of the local invasioi which agahiis 
influenced by the lactation period. According to de Bruin fresh 
milking animals more frequently become affected with the acute 
torm having inflammatory manifestations, while in old milkino< 
o^S^ secreh'or''' '''' itself mostly to the altered appearance 

n.rf^f^r"''/^ ^/i^^''^ '^''^^'^ ^' ^^'^* ^^^iier or later the affected 
pait ot the gland becomes destroyed. 

Sometimes the streptococci remain for weeks in the folds of 
the mucous membrane of the cistern without infecting the par- 

affPot^^' TT f f 'Tf ^,f "V^^^" ^''^''^ ^^^^^^^^1- qiii^kfv becomes 
attected. Unfortunately the disease does not often subside even 



g^ Ert'et't of Iiilcnial lullueuees. 

through the physiologically cliy period, and the affection re-ap- 
pears immediately after parturition. 

The destruction of all streptococci involves a difficult task for 
the entire body. The dissolution of the streptococci progresses 
only very slowly even in actively or passively innnunized animals. 
Living streptococci may be demonstrated in the abdominal cavity 
of test animals, numy hours after an intra-peritoneal injection. 
Not infrequently a delayed death appears in apparently recovered 
animals (v. Lingelsheim). The long strei^tococci appear to rep- 
resent specially adapted forms which have great tenacity. Never- 
theless at times recovery takes place. According to Zschokke the? 
relation between recovered and unrecovered cases is as 7 :5. 

According to the experience of the author in practice, infectious 
mastitis is not curable, or only with the greatest difficulty, and if 
so, always with a loss of productiveness, which even remains after 
the physiologically dry period. The chronic irritation causes a 
change in the connective tissue structure of the parenchyma of the 
udder so that the usual development of the gland during pregnancy 
cannot take place. The principal aim in treatment therefore 
should be prompt drying of the suspected udder, in order to make 
possible the most rapid and most complete recovery, which, ac- 
cording to Zschokke may be expected only when the quarter has 
been allowed to remain dry for a long time. 

This is also necessary in order to prevent a spread of the 
disease, which is to l)e feared since the hands of the milkers and 
milking upon the straw may transmit the infective agent to other 
quarters. Care should be taken therefore to keep the milk from 
the healthy quarters of the udder separate from the secretion of 
the affected quarter. 

As long as the most primitive requirements of clean milk 
production on the part of the milkers are so carelessly neglected, 
which unfortunately has been the case up to the present, the im- 
mediate drying of the affected quarter offers the only means of 
preventing the further spread of the disease. 

If, however, there is assurance that the affected animal or the affected quarter, 
respectively, is individually milked, and the milkers follow instructions, an atteuipt 
may be made by special frequent milkino^ (into a jar) to produce a hyperemia of the 
udder. With this method success can only be expected in the early stages. 

The extent of the spread of the disease may become obvious 
by the findings after examination of individual herds. In such 
cases it is necessary to milk each cow, or still better each quarter, 
separately. The results vary, depending on the technique of the 
examination. The lowest number of affections is olitained when 
only a clinical examination is made. This therefore does not suffice 
in order to eradicate the disease effectively, or to single out the 
affected animals. The data of the different authors vary relative 
to its occurrence. The following figures are given which were 
obtained by systematic examinations of entire herds. 



Streptococcic Mastitis. 85 



Out of 260 animals Trommsdorff found 15.6% affected, Riilmi 
31.25% out of 16 animals, Russell and Hoffmann found in 188 sam- 
ples 50% with ''streptococci." Savage found similar values 
(55%). 

The author examined from April 1, 1907, to November, 1908, 
1697 samples of milk from individual cows, and found in 348 sam- 
ples the typical signs of streptococcic mastitis. 

In 1908 and in the following years he has demonstrated : 

1908. No. of animals, 1695. Streptococcic cases 353 

1909. No. of animals, 738. Streptococcic cases 301 

1910. No. of animals, 597. Streptococcic cases 203 

1911. No. of animals, 876. Streptococcic cases 279 

Therefore 20.6; 20.9; 40.6; 34 and 31.8%, respectively, of 
the animals were found to be affected with streptococcic infections 
of the udder. 

If the milk of the individual quarters of the affected udder is 
examined various stages of the affection in the different parts of 
the udder may frequently be found. Out of 528 quarters of 
animals with affected udders 276, or 52.2%, showed lesions in 
individual quarters. 39.2% of the cows had the disease in one quar- 
ter, 25.9% showed it in two quarters, 18.5% in three quarters, and 
16.2% in all four quarters. According to Zschokke out of 662 
affected quarters 193 occurred in one quarter of the animal, 211 
in two, 109 in three, and 149 in all four quarters. 

The contamination of market milk with the secretions from 
animals with udder affections is relatively high. 

In spite of the fact that proof of the mixing of milk from 
affected udders with market milk is possible only in very pro- 
nounced cases (typical streptococcic chains with characteristics 
of animal origin), nevertheless the following results, obtained in 
examinations, demonstrated conclusively that the secretion from 
quarters affected with streptococcic mastitis had been added to 
the whole milk: 

1908, in 352 out of 1578 samples=22% 

1909, in 501 out of 1629 samples=40.5% 

1910, in 243 out of 1211 samples=20% 

1911, in 432 out of 1273 samples=33.9% 

The hygienic importance of the affection to the consumers of 
milk may be illustrated from the following data. 

I. Hoist, in 1894, had the opportunity of examining in Chris- 
tiania four series of affections of acute gastro-intestinal catarrh. 

I. Four ^rown persons and four children out of three families in the same 
street became affected four hours after the drinking of milk which originated upon one 
farm. Those persons who drank no milk or only that which had been boiled were spared 
with the exception of a child who became affected, although only slightly, after drinking 
boiled milk. 



gg Ef'tVot of Tnferiial Tiifluences, 



The appearance of the milk showed nothing abnormal, but it coagulated ou 
lioiling and sliuwed a tremendous number of bacteria, especially streptococci, which 
could not be distinguished from the Streptococcus piiofienes. 

The veteriiuiry examination coufinned the suspicion that a ])us-containing secre- 
tion was being yielded liy one cow. 

The milk from the cow with mastitis on the ilay in question was a<lded to tlio 
whole milk through the neglect of a newly hired attendant. 

2. Several hours after the drinking of raw milk five persons, and as found 
later other cases also became affected with acute gastro-intestinal catarrh. In this 
case a nulk dealer was implicated, and it was found ou inquiry that the milk con- 
tained secretion from a cow allected with streptococcic mastitis. 

3. According to the observations of Johaunesen two persons (mother and 
child) became sick after the drinking of milk. The milk was thin, liaky, and contained 
])us-like lumps. In the herd f!'om which this milk originated two cows were found 
to be affected with streptococcic mastitis. 

4. After the drinking of freshly drawn raw milk four children of the same 
family became affected with acute gastro-intestinal catarrh. The milk appeared ap- 
parentl,y normal, but contained large quantities of streptococci. It originated in 
a stable from which on the day in question a cow was sold ou account of mastitis. The 
milk from this cow appeare(l to have been mixed with the whole milk due to the 
neglect of a new milker (the regular one being sick). 

The affections which occurred in Stockholm with symptoms of fever, dullness, 
attacks of fainting, nausea, vomiting, diarrhea and cramps in the calf of the leg 
(nine families being involved), cannot according to the obtainable reports, be de- 
clared to be streptococcic infections. The milk, through the drinking of which the eases 
could be traced, originated from a dairy of 14 cows, among which one cow had mas- 
titis. It is possible that in this case an infection with bacteria of the paratyphus 
group, which plays an imi)ortant part in the development of acute mastitis, was con- 
cerned. 

Further contributions to the easuistics of "milk poisoning" were published by 
Jakobsen and Weigmaun and Gruber. 

II. In 1905, Jakobsen observed symptoms in several persons which he traced to 
the drinking of milk from one stable. The symptoms were diarrhea, vomiting and 
fever. Out of 17 persons, 10 who drank the milk became affected, while 7 who did 
not take any remained well. On May 30, 1905, other persons became affected. 

The examination of the 32 cows of the dairy showed a streptococcic mastitis 
in one animal. The cow was slaughtered and no further cases were reported. 

ITT. Edwards and Severn described an epidemic of follicular tonsilitis which de- 
veloped from the drinking of milk. They found in the exudate of the throat, and in 
the milk, in addition to other, bacteria pyogenic streptococci which as shown by the in- 
vestigation were also contained in the secretion of a cow affected with, mastitis. 

[In various cities of the United States epidemics of sore throat 
with sweUing- of the cervical lymph glands, colic, diarrhea and 
fever lasting several days have occurred which were traced to the 
nse of milk from cows affected with streptococcic mastitis. Such 
milk when examined was found to contain pus and streptococci in 
great abundance. — Trans.] 

IV. Lameris and Harreveld observed an outbreak of diarrhea among the inmates 
of a hospital after the drinking of boiled milk, which in part was obtained from cows 
affected from streptococcic mastitis. 

Whether the authors of the last cases are correct in their view 
that very likely a heat-resisting toxin brought on the disease, or 
whether the streptococci might remain alive in the milk foam or 
in the formed membrane, etc., as suspected by Jensen, it becomes 
evident that boiling does not carry with it an assurance that the 
danger from streptococcic milk is eliminated. If Jensen's sus- 
picion is correct a proof would be offered that even the smallest 



Table II. 










Ernst, Milk Hygiene. 



Streptococcic Mastitis. 



quantities of mastitis streptococci are sufficient for the production 
of severe intestinal affections. 

Y. On December 17, 1907, a sample of boiled milk was brought to the official 
milk control station of Munich; about a half hour after the drinking of this milk the 
man who delivered the milk, and his family, as well as a neighboring family using milk 
of the same origin, became sick. The milk contained 1.5:1000 streptococcic pus. It orig- 
inated from a large dairy. Three producers and one distributor were suspected. In 
tracing down the cause of the trouble two producers were found whose herds contained 
six animals with affected udders, their milk being mixed with the whole milk. 

The affection was marked by chills, diarrhea, headaches, and lasted not quite an 
entire day. The milk constituted the only common food partaken by all, and there- 
fore could be considered, although not with absolute certainty, as the probable cause. 

From tlie examples cited it may be seen that the drinking of 
milk which contains the secretion of streptococcic infected udders 
is capable, under certain conditions, of producing injurious 
effects upon the health of human beings. Considering the fre- 
quency of the disease, and the numerous cases where the prohi- 
bition of milking affected udders into the whole milk is disre- 
garded, it is to be wondered at that affections which could be 
traced to the drinking of such milk are not observed with greater 
frequency. 

This may be due to the fact that the secretion of affected 
quarters is usually very greatly diluted with the milk of healthy 
quarters, showing that the harmful actions are not necessarily 
induced Iby the predomination of the injurious material, and fur- 
ther it may also be due to the fact that the milk is mostly used 
after being boiled (Trommsdorff, Jensen). That the boiling of 
the milk is not alwa^^s sufficient to destroy the injurious properties 
may be seen from the cases of Hoist and Lameris and van Har- 
reveld; the milk of course is marketed in a raw state, and must 
therefore be judged in the condition in Avhich it is sold. 

The factors which induce the harmfulness of the milk from 
streptococcic animals are not known. Whether the injurious 
factors are due to the toxin produced by the streptococci of 
mastitis, or to the products of the disease, as for instance pus 
(Jensen), or to streptococci which, are pathogenic to man as such, 
cannot at the present time be definitely determined. This, how- 
ever, is of little importance from a practical standpoint. Some 
authors, such as Petruschky and Kriebel, consider that infected 
cows are the sources of milk streptococci, and that these are the 
principal cause of the summer mortality of children. Seiffert 
considers the streptococci originating from affected udders as 
more dangerous than the saprophytic streptococci which contam- 
inate the milk as a result of unclean milking. This view was also 
expressed by the author in May, 1908, and was confirmed by 
Trommsdorff. 

Neither studies nor animal experiments have succeeded up to 
the present time in proving the harmfulness of the streptococci 
by themselves, or the relationship of the mastitis streptococci to 
human pathogenic strains of streptococci, the animal experiments 



88 Effect of Internal Influences. 

offering" only a relative coiieliision on the susceptibility of the 
respective species of animals. 

The differentiation of the mastitis streptococci from otlier 
milk streptococci is however, ahsohitely necessary for milk control 
since only in the presence of typical mastitis streptococci can the 
milk dealers be held responsible, and be obliged to prevent the 
contamination. 

Escherieh and Hoist found streptococci in almost every sample of milk, and 
Hellens lepeatedly isolated them from milk. In 1840 in samples of market milk from 
Munit-h and vicinity the author succeeded in isolating f-trei)tococei either by culti- 
vation or recognizing them by bacteriological exaTiiination in 100% of the cases. Other 
investigators confirmed a positive finding in a strikingly high percentage. 

Beck — :Market milk of Berlin fi2 % 

Savage — 17 samples of market milk 100 % 

10 samples of market milk . . . 100 % 

Kaiser — INIarket milk of (i:a: 76.6% 

Briining — 28 samples of Lcipsic market milk !):> % 

Easten — 186 samples ."57 % 

Eastles — 185 samples from all parts of England 75 % 

The simplest proof of the constant occurrence of streptococci 
in market milk is the usual acid fermentation of cow milk induced 
by streptococci. 

A method for distinguishing- these frequently observed strep- 
tococci from mastitis streptococci has not yet been discovered, 
either through the fermentation of various kinds of sugars by the 
streptococci, or through the investigations of creatinin forma- 
tions, hemolytic action, acid formation or their actions in the pres- 
ence of various temperatures of cultivation. It should be borne 
in mind that the behavior of the various strains of mastitis strep- 
tococci has been described in such a variety of ways, that either the 
presence of remarkably numerous strains or a strong instability of 
characteristics, or confusion with saprophytic forms, must be 
accepted. 

The formation of acid by the streptococci is sometimes de- 
scribed as strong (Zschokke, Nenski, Groning, Kaiser, Heinemann, 
Miiller, Koning), at other times it appears insignificant (Sven 
Wall, Rullmann). 

Lohnic classes the streptococci of mastitis with the group of 
lactic acid streptococci, especially with the group of Streptococci 
g until cri, with close relationship to the group of Streptococci 
rosenbacli, having the following characteristics : 

"Form of the cells variable; capsule formation is frequent and appears to be as- 
sociated in certain forms with the presence of sugar in the nutritive media. Spores are 
not formed; the bacteria are Gram-positive; the intensity of the growth has no sig- 
nificance. Coagulation of the milk results, in these varieties, either through acid 
formation or through a rennet-like ferment; gas formation is rare; the pathogenicity 
varies remarkably." 

Miiller in his work on comparative examinations of lactic acid bacteria (Typ. giin- 
theri, etc.) presents the following: 

1. "The strains studied manifest marked differences either in their cultural or 
morphological characteristics with the exception of the strain causing "sour brood" 
among honey bees. ' ' 

2. "The action on carbohydrates is practically uniform." 



Streptoccccie Mastitis. 



89 



3. "Influencing individual strains relative to their acid formation in the sense of 
increasing or decreasing it, is possible. The characteristics which the freshly isolated 
strains possess are more or less permanent. ' ' 

4. "There exists a relation between the group of Streptococcus guntheri and the 
Streptococcus agalactiae since their capability of forming acid is about the same. ' ' 

5. "The oft recurring confusion of the two may be explained by certain similar 
forms of growth which both possess. ' ' 

6. "The supposition that the pathogenic streptococci represents lactic acid bac- 
teria of the Typ. guntheri which have adapted themselves to parasitic conditions, is sub- 
stantiated by the findings, since it was possible in the various strains of streptococci to 
produce transition forms, which correspond to the Typ. guntheri." 

Therefore from these few examples it may be seen that it is 
impossible to separate the streptococcus of infectious mastitis from 
the group of the lactic acid streptococci. Nevertheless it would be 
a great error to identify 

the ordinary lactic acid ^ig- ^'^^ 

streptococci with patho- 
genic streptococci of man 
and animals. 

If the fact is taken 
into consideration that 
some streptococci, as for 
instance that of Kefir, the 
streptococci of sour milk, 
and others, have a fa- 
vorable influence on the 
nutrition of man, the ne- 
cessity of their strict 
identification for control- 
ling the milk supply is 
apparent. 

Although it is not 
possible to absolutely dif- 
ferentiate one strain by 
cultural and biological 
characteristics, from a 
culture strain of differ- 
ent origin, nevertheless 
there are certain morphological characteristics of the streptococci 
in the -smears made from sediments, which are sufficiently constant 
to absolutely warrant the definite assertion that the streptococci 
in certain positive cases originated in an infected organ, and were 
not incidentally leading a saprophytic existence in the milk. 

It has been known for a long time that parasitic bacteria in 
the animal body, under the influence of the animal's protective 
strength, attain certain peculiarities of form which they lose under 
ordinary cultural conditions (under certain conditions it is possible 
to cultivate capsulated anthrax bacilli). Reference is made to 
the capsule of anthrax bacilli and to the formation of botryomy- 
cotic clumps by streptococcic forms. Consideration of the question 
whether such changes of form in bacteria are developed as protec- 




Sediment of milk, one day old, from an udder affected 
with streptococcic mastitis; (a) streptococci of in- 
fectious mastitis, (b) subsequently developed strep- 
tococci; 1, 2, 3 and 4, cells from the udder. 



90 



Effect of Internal Influences. 



Fiff. 



tive agents against the ininiunizing jjowers of the body, would re- 
quire too lengthy a discussion. The fact should suffice that strep- 
tococci originating from aifected udders almost invariably show 
signs of such transformation. It is not intended to assert that a 
steptococcus in milk which does not possess these form peculiari- 
ties is not a streptococcus of mastitis, or that it does not originate 
from the udder, and that under abnormal conditions (for instance 
cultivation at 37 deg. in raw milk or in serum) the streptococci 
Avhich are present could not undergo changes of form which under 
certain conditions simulate the forms of ''animal" streptococci; 
but for normal conditions of milk inspection the morphological 
characteristics of animal streptococci offer certain definite appear- 

a n c e s of recognition 
which have always been 
joroved by control tests 
made in the respective 
stables. 

These characteristics 
are the following: 

The streptococcus 
takes on a diplococcus- 
like separation, the cocci 
apparently press each 
other, become disc- 
shaped, and in profile ap- 
pear like a dash. They 
stand at right angles to 
the length of the chain 
(compare with equine 
distemper streptococci 
according to Rabe.) A 
fine capsule is formed 
around the "animal" 
milk streptococci, which 
is sometimes more, at 
other times less pro- 
nounced. This sometimes swells to a broad mucin capsule (com- 
pare Lingelsheim on streptococci, Wassermann-Kolle's Hand- 
book of pathogenic micro-organisms III, pp. 309 and 310, and 
Sven Wall, p. 29). The endococeus, especially in short chains is 
spherical or swollen to a club shape. 

With slight practice one almost invariably succeeds in dis- 
tinguishing, by one or the other given characteristics, the "animal" 
mastitis streptococci from streptococci which have gained access to 
the milk accidentally (even though they may also possibly be de- 
scended from "animal" mastitis cocci). 

In this way the author succeeded, from April, 1907, to Novem- 
ber, 1908, in demonstrating l)y the aid of smears that_ secretions 
from cows with streptococcic mastitis were mixed with market 




Sediment of market milk in which the typical _ animal 
forms of streptococci (a, b, c) make possible a diagnosis 
that tlie milk contains the secretion of an animal af- 
fected with streptococcic mastitis in spite of the oc- 
currence of other forms of streptococci (d and e). 



Streijtocoeeie Mastitis. 



91 



milk. Out of 1840 microscopically examined samples 336, or 
18.26% showed the presence of such an infection. 

In 91 cases, or 4.945% the changes were not very pronounced ; 
later control however proved that milk from cows affected with 
yellow garget had been mixed with these shipments. 

18 . 26 % -h 4 . 945 % = 23 . 205 % , proved contaminated with 
streptococcic pus out of 1840 milk samples. 

Miiller intended in his work to distinguish milk streptococci, 
especially the streptococci of mastitis, from strains of streptococci 
pathogenic to man. In confirmation of the work of Nieber, Fischer 
and Berger, Miiller came 

to the conclusion that the I'ie- 19. 

recognition of milk strep- 
tococci pathogenic to man 
is impossible. Although 
milk streptococci as a 
rule coagulate milk some- 
what more quickly, there 
are also strains which 
coagulate milk somewhat 
more slowly, and strains 
which dissolve the blood 
cells in Schottmiiller 's 
blood agar, and these in 
their agglutination value 
stand very close to the 
pathogenic streptococci 
of man, that is, they ag- 
glutinate even in dilu- 
tions of the serum of 
1:400—800. At the same 
time several of the abso- 
lutely pathogenic strains 
fail to give any agglu- 
tination, and other ap- 
parently saprophytic va- 
rieties give a higher ag- 
glutination value. Bau- 
mann proved that there is no uniform agglutination value of the 
individual kinds of streptococci, and that spontaneous agglutina- 
tion frequently appears in tests of their cultures. 

Together with Horauf, the author found that mastitis strains 
show similar characteristics on Schottmtiller's blood agar to the 
less pathogenic strains of man, a fact which has recently been con- 
firmed by Gminder. Lingelsheim makes the statement that strepto- 
cocci producing toxins are always obtained from subacute and 
chronic processes. 

Acid formation and milk coagulation are common to the entire 




Sediment of red milk. Many red blood corpuscles, 
several polynuclear leucocytes and colostral cells. 
Streptococcus brevis with capsules. 1 X 1000. 



92 



Effect of Internal Influences. 



Fio-. 20. 



group of pathogenic streptococci. Of the pyogenic strains of man, 
according to Andrewes, the iStreptococcus pyogotes and the Strep- 
tococcus viitis produce acidity without coagulation. Sven Wall 
proved these characteristics from the mastitis strains isolated by 
liim. According to Adametz, the mastitis cocci sometimes coagulate 
very intensely, the same as is the case with the streptococci of 
enteritis of sucklings (Petruschky). The fermentation in various 
sugars using Gordon's bouillon mixtures, varies greatly with the 
different pathogenic streptococci and milk streptococci, so that the 
possibility of differentiation by this means is quite impossible, 
which is likewise the case by testing their virulence on small test. 

animals. Pathogenic 
strains may at times show 
great variations of viru- 
lence, while according to 
Heinemann strains of the 
Streptococcus lacticus 
may become virulent by 
passage through rabbits, 
until they Avill produce 
changes in rabbits which 
correspond in their ap- 
pearance, extension and 
character, to those caused 
by pyogenic strains re- 
covered from man. 
Through their action on 
animal bile, or on sodium 
taurocholate, M a n d e 1- 
baum differentiates the 
Streptococcus miicosus 
and Pneiimococcus from 
Streptococcus pyogenes 
and other streptococci 
(Neufeld, V. Levy). The 
author used the mastitis 




Sefliment of milk from an udder with acute inflammation. straiuS llC had OU haud 

Short forms of streptococci. 1 X lOoi). ,,-, -• -, -i 

on cattle, hog, horse and 
chicken bile, but failed to observe either a clearing of the culture 
media or an influence upon the form and appearance as shown by 
the microscope. 

The establishment of the ''virulence number" through phag- 
ocytic experiments also fails to yield the desired result. 

In short up to the present time the absolute separation of 
culture strains of varied origin, the differentiation of saprophytic 
streptoccoci from mastitis streptococci, and these from pathogenic 
streptococci of man has not been successfully accomplished. We 
have, however, in certain morphologic indications, for instance 



streptococcic Mastitis. 



93 



the cross-position of the segments, the capsule-like covering and 
other characters, a way of distinguishing streptococci originating 
in the udder of an animal from such as have subsequently gotten 
into the milk. If these distinguishing signs are present then smears 
from the sediment of market milk permit the deduction that secre- 
tion from an affected udder has been included in the milk. If, on 
the other hand, these signs are not present in the streptococci of the 
milk, it cannot be asserted that the milk is not contaminated with 
the secretion of affected udders, 
it is not 

Fig. 21. 



Although 



IS 

known what factors 
(streptococci, toxins, in- 
flammatory products) 
convey the unwholesome- 
ness to the milk, and al- 
though in spite of the fre- 
quent occurrence of mas- 
titis injurious effects re- 
sult with relative rarity, 
nevertheless the secretion 
from udders affected with 
streptococcic mastitis, 
and mixed milk which is 
contaminated with such 
secretion should be con- 
sidered capable of im- 
pairing the human health, 
since 

1. There are known 
cases in which severe dis- 
turbances of health re- 
sulted from the ingestion 
of such milk. 

2. The investiga- 
tions of streptococci 
scientifically justify the 
suspicion of harm arising from their ingestion. 

What are the conditions of the mastitis streptococci among 
themselves? Formerly a Streptococcus hrevis and a Streptococcus 
longus were distinguished, but it was shown that these distinguish- 
ing features were not absolute (Staeheli). The differences of the in- 
dividual strains and the forms of their growth in culture are as in- 
constant as their pathogenicity, acid formation, and other biological 
characteristics, so that, as expressed by Kitt, it would be necessary 
to distinguish as many varieties as there are mastitis cases if it 
was desired to accept the differences of the individual mastitis 
strains as indicative of different varieties. All the smaller and 
greater differences should be considered as indications of adapta- 



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Streptococcic pus from milk of a cow with streptococcic 
mastitis. Streptococcus longus. 1 X 1000. 



94 



Effect of Internal Inlluenoes. 



tioii to the various energies of reaction of the various animals and 
organs, and as the investigations of the author showed, to energy 
reaction of the same milk ghmd at different times. For instance it 
appears that certain changes in form liear a definite rehition to 
the number of leucocytes in the milk. Thus the author obtained 
the following results in the same quarter of a cow examined at dif- 
ferent times : 

L. — Leucocytes. 

Sir. — Streptococci. 

Dec. 17, 19ns. Jan. 4, 1909. Jan. 20, 1909. Jan. 2o, 1909. 

Cow Xo. 29 L. 8tr. L. Str. L. Str. ].. Str 

1 rio-htfore 0.3 .1 0..5 0.2 

2 left fore 0.2 0.9 Bipl. 0.4 brevis 2.0 hrevis 

3 rii-ht hind 500.0 longiis 2.0 brevis 1.9 brevis 3.0 brevis 

4 left Ivinil 500.0 longus 20.0 longus 0.5 brevis 10.0 longus 

Cow Xo. 34 Dec. 17, 1908. Jan. 5, 1900. Jan. 1('>, 1909 Jan. 29. 1909. 

1 right fore 0.1 0.2 0.1 0.2 

2 left fore 0.2 Dipl. Drops 0.3 0.5 

3 right hind 0.4 Dipl. 0.3 Dipl, 3.0 longus 50.9 brevis 

4 left hind 0.3 Dipl. 0.5 brevis 4.0 longus 60.0 brevis 

Dec. IS, 190S. Jan. 4, 1909. 

Cow Xo. 31 L. Str. L. Str. 

1 right fore 0.5 Dipl. 0.3 brevis 

2 left fore 1.5 200.0 medium sized 

3 right hind 1.2 Dipl. 1.8 brevis 

4 left hind 1.3 brevis 0.9 Dipl. 

Cow Xo. 33 

1 right fore 2.0 brevis 0.3 Dipl. 

2 left fore 0.5 0.2 

3 right hind 1.3 brevis 20.0 longus 

4 left hind 0.9 brevis 10.0 longus 

Cow Xo. 58 Dec. 19, 1908. Jan. 5, 1909. 

1 right fore 0.1 0.5 Dipl. 

2 left fore 0.4 brevis 0.3 Dipl. 

3 right hind 0.3 0.1 

4 left hind 0.1 0.1 



These differences in the forms of streptococci may be seen dur- 
ing one milking on the same animal, if they are compared at the 
beginning, the middle and at the conclusion of the milking. These 
differences are only slight, so that no definite conclusions should be 
drawn from them. 

If however the results from various animals are compared it 
may be seen, as already indicated above, that certain relations exist 
between the number of leucocytes and the forms of the streptococci 
since the streptococci become longer as the number of leucocytes 
increases. The experiments extended from December 11, 1908, to 
February 8, 1909, and include three stables with a total of 149 
cows. 

Of these 149 cows 59, or 39.6% were more or less affected. In 
most animals (140), all quarters were separately examined and 



Streptococcic Mastitis. 95 



showed that out of 560 quarters 112, or 20% were affected. Forty- 
two of these gave at tmies a greater, at other times a smaller secre- 
tion with a distinctly changed consistency. The other 70 manifested 
the infection only after sedimentation, or only through microscopi- 
cal examination. Some of these 12 quarters were successively (see 
above) examined, so that the material used for smears from af- 
fected quarters, and which had been microscopically examined, 
amounted during the period mentioned, to 134. 

Fifty-five affected quarters showed the Streptococcus hrevis, 
32 the Streptococcus longus; in 47 the infective agent was recog- 
nized in the form of a diplococcus. The 47 quarters with diplococci 
had as a rule a very small leucocytic number. In values of over 
2.0, longer coccus-chains were always observed. 

32 quarters out of the 47 had . 5 :1000 leucocytes 

12 quarters out of the 47 had 1 .0 :1000 leucocytes 
3 quarters out of the 47 had 2.0 :1000 leucocytes 
In the 55 cases with Streptococcus hrevis the change in the 
leucocytic number varied to a greater extent. 

In 18 it represented 0.5:1000 or 32.73%. 

In 14 it represented 1.0:1000 or 25.47%. 

In 8 it represented 2.0:1000 or 14.55%. 

In 3 it represented over 2.0:1000 or 5.45%. 

In 12 it represented 5-20 and more :1000 or 21.82%. 
The 32 longus-cases were divided as follows : 

Leueocytic Quantity. Number of Cases. Percentage. 

Under 0.5:1000 1 3 125 

up to 1.0:1000 1 3 125 

up to 2.0:1000 3 9.375 

up to 5.0:1000 3 9.375 

up to 20.0:1000 3 9.375 

up to 100 and more:1000 21 65.625 
In other words : 

In leucocytic quantities 

Tip to 0.5, 63.00% showed 85.0% brevis, 2.00% Dipl. longus 

Up to 1.0, 44.40% showed 51.9% brevis, 3.70% Dipl. longus 

Up to 2.0, 17.65% showed 64.7% brevis, 17.64% Dipl. longus 

Up to 5.0, 0.00% showed 50.0% brevis, 50.00% Dipl. longus 

Up to 20.0, and more 0.00% showed 33.0% brevis, 66.60% Dipl. longus 

The leucocytic values will be taken up again later in the dis- 
cussion of the "Trommsdorff" test. 

_ From this tabulation it may be seen that the length of the 
chains actually grows with the increase of leucocytes, or with the 
amount of sediment. In high leucocytic values and short forms 
of the infective agents, the latter are frequently present in exceed- 
ingly large qantities. 

The opinion that the form of the streptococcus represents an 
adaptation to the energy reaction of the respective animal and or- 
gan is thereby substantiated especially when the streptococci are 



J)() Effect of Inlenial Inlluences. 

found in the secretion of one and the same ])ai't of the udder of a 
cow at different times. 

In the same way it is impossible to establish rnles for definite 
differentiation of the strei)tococci of the yellow i>aroot amon,^- them- 
selves throni^h the stndy of their niorpholoi>ical relations, by com- 
parison of their biochemic characteristics or the pathogenic viru- 
lence of individual strains, since the acid production and 
acid susceptibility which are present in mastitis streptococci at first 
may be easily changed by artificial means, and individual strains 
have proven the possession of stronger, others a weaker pathogenic 
action for test animals (Groning, Sven Wall). 

The author does not desire by any means to establish a theory 
of unity for mastitis streptococci. To be sure there are marked 
differences in the various strains, especially in regard to the pro- 
duction of clinical symptoms, which cannot be attributed alone to 
the variation of virulence, and to unequal resisting powers. 

It is possible that with the aid of newer methods of differ- 
entiation (blood media, etc.) it will be possible to establish a fun- 
damental type of mastitis streptococci in strains freshly cultivated 
from animals. Even if with the continuance of cultivation new 
characteristics, as for instance hemolytic properties, may be 
acquired by the cultures, and the earlier characteristics become lost, 
the characteristics acquired by the respective strains of streptococci 
in their former growth may remain constant for a sufficient length 
of time to permit the establishment of the type of varieties, as has 
already been the case with the streptococci of man (Petruschky, 
Schottmuller, Baumann, Schulze and others). Enrst, Gminder and 
others have demonstrated that the mastitis streptococci mostly 
correspond to the mitior sen viridans or mucosus hom. group, 
respectively. 

Based on the grounds previously described, milk hygienists, 
bacteriologists, children specialists and veterinarians sometimes 
more and at other times less imperatively have demanded the ex- 
clusion of cows with streptococcic mastitis from the production of 
milk (Jensen, Weigmann, Rievel, Sven Wall, Euhm, Trommsdorff, 
Seiffert, Ernst and others). 

This requirement is natural from the hygienic standpoint, but 
its practical execution is rendered very difficult by the remarkable 
prevalence of the disease, and as a matter of fact as long as the 
general control of production and the examination of milk of indivi- 
dual cows are not required a thorough enforcement cannot be 
hoped for. 

For the present the exclusion from the market of all milk which 
shows changes in a recognizable way, as for instance through a 
collection of yellow sediment, should be considered satisfactory. At 
the same time from an economic standpoint only milk from affected 
quarters should be excluded, while the sale of milk from healthy 
quarters should be allowed. 



Udder Tuberculosis. 



97 



TUBERCULOSIS. 

Occurrence of Tuberculosis in Cattle. 

Tuberculosis of the udder in cows appears with relative fre- 
quency, corresponding to the frequent occurrence of tuberculosis 
in cattle. 

Tuberculosis in the udder is manifested in different forms, 
the circumscribed, lobular, focal tuberculosis and the diffuse tuber- 

Fia-. 22. 



im 



Wa)>^<tm^^ '*T^ -a: 









Tuberculosis of the udder. Progressive miliary form. 

culosis extending over and infiltrating the entire udder. Two of 
the different forms may be present at the same time in the organ, 
and from one form through accentuation of the infection the other 
forms may result. 

Clinically tuberculosis is manifested by nodular swelling or 
hard enlargement of the affected quarter, and with enlargement and 
painless nodular swelling of the supramammary lyniph glands. 
These changes, hovf ever develop very slowly and tlie milk from such 
infected quarters for weeks and months may contain millions of 



98 Tuberculosis. 



tubercle bacilli without the udder indicating- any special lesions, 
and without the milk showing any noteworthy changes. 

The quantity of the secretion from a tuberculous quarter is at 
first uninllueneed, or only slightly so; later it is considerably dimin- 
ished. For a long time it is of a normal appearance; later it 
generally becomes thick, transparent, watery, intermixed with small 
flakes, or again it may become thick, yellow, pus-like, depending on 
the intensity and extension of the lesions in the udder and the in- 
fluence of the general health of the cow. 

Tuberculosis of the udder as a rule is of an embolic character, 
and rarely represents the result of a galactiferous infection. No- 
card, Meyer, Calmette and Guerin, and Zwick succeeded in pro- 
ducing tuberculosis of the udder of various characters, by injections 
of bovine and human tubercle bacilli into the milk duct of the teats. 
The pathologico-anatomical appearance in these instances was the 
same. 

The extent of the spread of tuberculosis in cattle in general is 
best indicated by the statistics of abattoirs in the different states. 

In Germany in 1904, 17.89%, in 1905, 19.16%, in 1906, 20.66%, 
and in 1907, 21.21% of cattle were retained on account of tuber- 
culosis, and 0.26%, 0.30%, and 0.35%, respectively, on account of 
tuberculosis of the udder. In Bavaria in 1898, 5.7%; 1900, 6.0%; 
1902, 6.8%; 1904, 9.2%; 1906, 10.31%, were tuberculous. 

The spread of tuberculosis is especially assisted by exposure 
in stabling (in 1907, 7.28% of young stock, 18.54% bulls, 22.55% 
steers, and 29.62% of cows were found to be tuberculous on 
slaughter, against 5.3%, 13.9%, 18.3% and 25.3%, respectively, 
in 1904), and forced feeding while the percentage in pasture ani- 
mals diminishes considerably, and in range cattle tuberculosis is 
practically unknown. In Prussia the total infection from 1898 to 
1906 is estimated at 16.09 to 23.4%, in Saxony from 30.46 to 37.58%, 
from 1898 to 1908. In France in certain localities the infection ex- 
ists in 30 to 40% of the stock, an average of 10%. In other 
countries similar conditions obtain. 

If the abattoir findings are not considered as indicative of real 
conditions, and delicate biological methods are employed which 
prove that an animal is infected with the tubercle bacillus (with- 
out however manifesting anatomically demonstrable changes) the 
increase of the numbers is considerable. 

In Saxony from 1891 to 1897, in round numbers two-thirds oH 
the cattle were found to be infected through the aid of tuberculin. 
Ostertag accepts 25% of the cattle as infected in northeruGermany 
and around Stuttgart, basing his estimate on sample testing in the 
various localities. In France from 50-80% of the animals reacted, 
in Great Britain 27%, in Austria 14-60%, in Hungary up to 35 . 18%, 
Belg-uim 48.8%, Norway 22.8%, Sweden about 31%, Finland 
13.7%. In Denmark during the first years of the tuberculosis 
eradication 38.5 to 40% of the animals gave tuberculin reactions, 
while later only 8.5% reacted. 



Frequency of Tuberculosis. 99 

[The extent of tuberculous infection among cattle in the United 
States is indicated by the statistical reports of the Federal Bureau 
of Animal Industry. According to these figures out of 400,000 
cattle tested, there were 37,000 reactors or 9.25%. The majority 
of these animals were dairy cattle, from which fact the conclusion 
has been drawn that approximately 10% of the dairy cattle in this 
country are affected with tuberculosis. On the other hand the meat 
inspection statistics show that 6,978,293 cattle were slaughtered in 
official establishments during 1913, of which 75,870 were found 
tuberculous, suggesting that probably 1% of beef cattle are affected 
with tuberculosis to some degree, — Trans.] 

The relative frequency of tuberculosis of the udder corres- 
ponds to the numerous occurrences of bovine tuberculosis. 

According to Bergmann 3.5% of the tuberculous cows slaugh- 
tered at Malmo were also affected with tuberculosis of the udder. 
Ostertag estimates the appearance of tuberculosis of the udder in 
0.1 to 0.3% for Germany. These figures of course increase in lo- 
calities in which the other forms of tuberculosis occur with greater 
frequency. Thus Meyer-Stendal report that out of 818 cows 4% 
showed udder tuberculosis. Meissner found in 1910 from all cows 
examined in Posen 0.32% affected with udder tuberculosis. 

Bugge mentions out of 16,050 cows included in the eradication 
work at Schleswig-Holstein in 1906, the presence of tubercle bacilli 
in 30 out of 318 examinations of mixed milk, and in 27 out of 562 
individual milk tests of suspected cows. 

In 1907 the tests for tuberculosis of 258 samples of mixed 
milk, revealed tubercle bacilli in 35 while out of 597 individual milk 
samples, tubercle bacilli were found in 32, which corresponds to 
0.14% of open udder tuberculosis in the 23,278 examined animals 
(pulmonary tuberculosis 5.1%). 

In 1908 these numbers amounted to 0.124 to 2.644% respec- 
tively out of 38,454 animals. 

In the presence of such an extension it should be not at all 
surprising that market milk contains tubercle bacilli with extraor- 
dinary frequency. Examinations for this purpose were under- 
taken as early as 1893 by Montefusko in Naples, in 1894 by Fl'iis 
in Copenhagen, in 1895 by Obermuller and Fiorentini, in 1898 by 
Petri, 1900 by Beck in Berlin, in 1895 by Zacharbeko in Petersburg, 
1897 by Massone in Genoa, Buege in Halle, Boyce and Delepine in 
Liverpool, Klein in London, Nonewitsch in Wilna, Stepanow in 
Kasan, Bujwid in Krakau, and in 1905 to 1906 by Eber in Leipzig, 
with varying results. 

The numbers of tubercular infection of market milk obtained 
(other investigators for instance Brusaferro, Roth, Schuchardt, 
Groning, Petri, Rabinowitsch, Hermann and Morgenroth, Asclier, 
Coggi, Bonhoff, Herbert, Markl, Herr and Beninde, Eber and others 
experimented with butter and cheese) fluctuated between and 
100%. 



100 Tuberculosis. 



Autlior. 

ObcM-nnillcr . 
Bue^e 


Samples. 
1.". 

6 


Petri 


64 


Beck 


51) 


Proskaiicr . . 
Seelit!,'iiiaiin . 
Croiicr 


9 

f) 

1 :] 


Eber 


210 



It is to be expected that all market milk, no matter of wbat 
orii>in, may occasionally be infected with tubercle bacilli; all milk 
in the production of which no special care is taken in the selection of 
the milking animals and no clinical examination or tiibercnlinization 
of the animals has been undertaken, should l)e suspected of contain- 
ing tubercle bacilli, and the larger the herd which produces the 
milk, the greater the danger. 

German investigators established the following tigures for the 
presence of tubercle bacilli in market milk: 

riaee. TuIk rcular %. 

Berlin 61 

Halle 33.3 

Berlin 14 

Berlin 30.3 

Market milk Berlin 55.5 

Dairies nnder veterinary control .. 0. 

Danish milk ." 38.5 

Leipzig 10.5 

[The percentage of tubercle bacilli found in the milk supply 
of large cities in this country has been accurately determined in 
only a few instances. In 1907 Anderson proved that in Washing- 
ton, D. C, 10.7% of the dairies supplied milk containing virulent 
tubercle bacilli, Schroeder found 7.7% of the 26 dairies examined 
w^ere distributing infected milk to Washington, D. C, while still 
later Mohler showed that abont 3% of the 73 samples of milk ex- 
amined contained tubercle bacilli. The apparent discrepancy in 
these results may be readily explained by the fact that during the 
last 6 years strenuons efforts have been carried on by the Bureau of 
Animal Industry to eradicate tuberculosis from among these herds, 
■with the result that in the District of Columbia the number of 
tuberculous animals has been reduced from 18.8^0 to 1.2% in 
1914. Hess has found that 17, or 16%, of 107 samples of milk dis- 
tributed in New York City contained virulent tubercle bacilli, 
while Campbell made extensive investigations of the occurrence 
of tubercle bacilli in the market milk of Philadelphia, and found 
18 or 13 .8% of the 130 samples examined to contain living bacilli of 
tuberculosis. — Trans.] 

Under What Conditions Do Tubercle Bacilli 
Enter the Milk? 

The infection watli tul)ercle bacilli is natural when the animal 
is affected wdth tuberculosis of the udder, or may occur indirectly 
wdien through contamination of the udder wdtli feces in pulmonary 
or intestinal tuberculosis, urine or vaginal secretion in kidney or 
uterine tuberculosis, or Avith infected straw, tubercle bacilli are 
brushed off from the soiled udder into the draw^n milk, or when in 



Infectiousness of Milk. 101 



open tuberculosis of the lungs the bacteria get into the milk through 
the air or straw. 

As early as 1869, prior to the discovery of the tubercle bacil- 
lus by Koch in 1882, Gerlach proved the infectiousness of milk 
from highly tuberculous animals through feeding and inoculation 
experiments. This was also emphasized by Ziirn, Kleins, Sommer, 
and in 1880 by Bollinger, who first pointed to the fact that the milk 
of a tuberculous cow in which the udder is not noticeably affected 
may contain tubercle bacilli. The same results are shown by the 
works of Stein, Bang, Hirschberger, Ernst, Schroeder and Fiorenti, 
Avho succeeded in producing tuberculosis in test animals with milk 
of tuberculous cattle, even though there was no udder tuberculosis 
jDresent. Milk from tuberculous udders always has lieen proved 
to be especially dangerous (May, Bang). 

If special care were exercised in milking, it not infrequently 
happens even in extensive, generalized tuberculosis that the in- 
oculated animals remain well; thus Xocard from injecting milk of 
54 cows affected with generalized tuberculosis succeeded only in 
3 cases in producing inoculation tuberculosis. Therefore it ap- 
pears that in spite of a generalized tuberculosis when udder tuber- 
culosis is not present, tubercle bacilli are not always excreted 
with the milk; the possibility of elimination however, that is, that 
the milk of such a tuberculous cow may contain tubercle bacilli, 
should at all times be given consideration. 

Is milk liable to be affected when tulierculosis cannot be clin- 
ically demonstrated in suspected cows, or when they appear healthy 
and yet react to tuberculin! Are tubercle bacilli eliminated only 
with the milk from animals affected with tuberculosis of the udder, 
or also in cases where the udder is not affected by tuberculosis! 
These questions may be answered at the present time with great 
certainty, namely, that tubercle bacilli of cattle are eliminated with 
the milk as a rule only in animals which are affected with tubercular 
mastitis. This question is of especial interest in the eradication of 
tuberculosis in the dairy herd, since it is well known that calves and 
hogs are highly susceptible to the tubercle bacillus of cattle. It 
will be advisable therefore to refer to the more important publica- 
tions on the elimination of tubercle bacilli with the milk, before 
entering into the c{uestion of the harmfulness of such for man. 

Delepine, Eavenel, Eabiiiowit?ch aud Kempner, Gelirmanu, Gehrmann and 
Evans, Moiissu and Mohler obtained positive results from milk of animals not clini- 
cally affected, but reacting to the tuberculin test, through inoculating or feeding of test 
animals. 

Other investigators, as Martel and Guerin, also Hirschberger, aimed to solve the 
qnestion by inoculating the milk of slaughtered animals or glandular substance from 
ndders of reacting animals. Their work also frequently gave positive results. ^7? of 
ihese authors therefore, conclude icith great certaintii that tubercle hacilli maii he 
eliminated icith the milk even from animals u'hich are not clinicaUy afected with tii- 
herculosis. 

Other views are supported by Ascher. Muller, Ostertag. Stenstrom, McWeeney, 
Pusch and Hessler as the result of their negative findings, namely, if the experiments 
were conducted under the most painstaking requirements and all contaminations through 



102 Tuberculosis. 



infectoil straw, etc., u\M-e avoiilcil as imich as possihio, tlu\v failed in spite of numerous 
pvperiifeiits in proiiuciiio- tul;ortni)osis with milk from a tuherculiii reacting animal, and 
fi(M|ueiitly not even with the milk from an animal clinically affected, but free from 
tuberculosis of the udder. 

From the standpoint of milk hygiene the fact is important that 
in the work of tuberculosis eradication by the agricultural societies 
the examinations for tubercle bacilli in the mixed milk of individ- 
ual herds were mostly negative after the clinically affected tuber- 
cular animals had been eliminated. According to the works of 
Muller and llessler until July 1907, 2,949 samples of mixed milk 
of individual herds were examined; all of these herds were sub- 
jected to the Siedamgrotzky-Ostertag method of eradication. From 
.■)0 to 200 cows particii)ated in each test and 156 herds gave milk 
free of tubercle bacilli. As eliminators of tubercle bacilli were 
found : 

Two cows with udder tuberculosis, 8 times each. 

One or more cows with tuberculosis of the uterus, 16 times. 

One or more cows with tuberculosis of the uterus, 6 times. 

Once kidney and uterine tuberculosis. 

Once pulmonary and intestinal tuberculosis. 

Once a cow whose saliva contained tul)ercle bacilli and 
19 times open pulmonary tuberculosis. 
In five positive tests there was no clinically demonstrable form 
of tuberculosis, and the subsequent tests of immediately drawn con- 
trol samples remained negative. These five cases were observed in 
the beginning of the eradication work. 

Tlie remaining 2,793 milk samples were free of tuberculosis in 
spite of the fact that among tlie animals of these herds there were 
surely a great number which would have positively reacted to 
tul)erculin tests. 

The five cases observed at the beginning of the eradication work, in whieli the 
milk contained tiihercle bacilli, altliough elinicallv o])en cases of tuberculosis could not 
be found on stalile examination, are explained by Hessler in that the milk liecame contami- 
nated with jiarticles of the feces from pulmonary cases of tuberculosis, which had not yet 
developed clinically. This is also suggested by the smaller number of bacilli found in the 
milk. 

Tu1)ercle bacilli therefore occur in the milk in great numbers 
when animals with open tuberculosis, and tuberculosis of the udder 
stand in the stable. Milk from animals which manifest their tuber- 
culosis by a positive tuberculin reaction, will usually be free from 
tubercle bacilli. Such cows belong to the least dangerous class. 
Nevertheless the investigations of Eabinowitsch, Kempner, Eav- 
enel and others, who obtained positive inoculation results with milk 
from reacting animals, prove that such milk may at times contain 
tubercle bacilli in small numbers. Ordinarily however this will 
uot be the case, and the milk of such animals may, as a whole, 
be considered free from tubercle bacilli. 

Therefore it appears evident that under present conditions of 
milk production the ingestion of tubercle bacilli with milk is possi- 
ble at almost all times. 



Tubercle Bacilli Types. 



103 



What Danger Threatens Man Through Ingestion of Milk Which 
Contains Bovine Tubercle Bacilli? 

In order to answer this question it is necessary to refer 
to the development of tuberculosis in man, and to consider the fac- 
tors which are necessary for an infection of his body. 

These factors in addition to the toxicity of the infective agent, 
and the quantity in which it has the opportunity to enter the body, 
depend upon the avenues of infection which it takes and the local 
and general resistance of the attacked individuals towards the spe- 
cific infective agent. 

There is perfect agreement relative to the virulence of the 
bovine tubercle bacillus for man. The bovine tubercle bacillus is a 
strain of the tubercle bacillus with such pregnant characteristics 
that it is almost invariably possible to classify it separately from 
other strains when obtained in culture, that is, to distinguish the 
bovine tubercle bacillus from the bacillus of the human type. 

These bacilli are distinguished as the typus bovinus and 
typus humanus (only these two types need to be considered from 
the standpoint of milk hygiene) which are characterized by the fol- 
lowing peculiarities : 



Typ. Bovinus. 

The growth is delicate and 
in the thin film small wart-like 
colonies develop; on bouillon a 
mesh-like fine membrane with 
wart-like prominences develops 
proliferating downward, or a 
membrane of tissue-paper thick- 
ness results ; the bouillon is 
probably neutralized and finally 
becomes alkaline. 

The bovine tubercle bacil- 
lus is as a rule of greater 
toxicity for smaller mammalia. 
Rabbits develop through intra- 
venous injections of the bacillus 
(0.001 gm.), a generalized tu- 
berculosis from which the ani- 
mals succumb inside of three 
weeks. When 0.01 gm. is in- 
jected under the abdominal skin, 
it produces in a short time, gen- 
eralized tuberculosis. 

Cattle succumb readily to 



Typ. Humanus. 

The growth is a luxuriant, 
uniformly thick and wrinkled 
membrane, which proliferates 
on the wall of the tube. The 
growth is the same in bouillon; 
the degree of acidity of the 
bouillon is usually at first 
diminished, later increased. 

0.001 gm, of bacilli of the 
human type intravenously in- 
jected produces after months 
only a chronic form of tuberculo- 
sis (joints, kidneys, lungs, 
testicles). 

The injection under the ab- 
dominal wall produces only local 
lesions. 

Inoculated into cattle the 
bacilli of the human type (0.05 
gm. subcutaneously), produce 
only slight or no pathogenic ac- 
tion. The process remains 
local, and extends only to the 



104 



Tuberculosis. 



infection witli the typus bovin- 
ns, from an extensive form of 
tnberenlosis. Guinea pigs die 
more quickly from an inocula- 
tion with bovine tubercle bacilli 
than from an inoculation with 
the bacillus of human type. 



neighboring glands; a great 
healing tendency prevails. 

Intravenous injections of 1 
mg. of the typus humanus into 
the vein of a mouse will show it 
to possess a greater resistance 
than when inoculated with the 
typus bovinus. 

Ill the last 10 years about 2000 strains of tubercle bacilli from man anil cattle 
have been cultivated and studied. In these studies even further differences were found 
Avbich, however, are not as constant as those given above; for instance, the bacillus of 
the human type in glycerin bouillon cultures is delicate, slender, slightly curved, and 
of beaded staining qualities, whereas the bovine strain is regular, plump, thick without 
granular difl'erentiation in staining, and frequently with swollen ends. The pigment 
formation on glycerin potato is more typical of the human type than the bovine type. 
The former when placed on serum in hermetically sealed glass tubes remains viable for 
twelve months, the latter for over a year. 

Contrary to the views of many investigators of tuberculosis, 
Nocard, Hueppe, Von Behring, Eomer, de Jong and others support 
the theory that the tubercle bacillus adapts itself to the infected 
animal and becomes transformed as a result of its environment. 
Eabinowitsch, Dammann and Eber have also supported this trans- 
formation theory. The latter especially attempted to prove by ex- 
tensive experiments and investigations that Bacilhis liumcoius, 
by passage through cattle, changes into the bovine type'. This 
question however appears at the present, to be decided in favor 
of the stability of the bacillus. 

Tt has at least been shown with six various strains of the human type, that in 
passage experiments through 2 to 7 cattle, in from 247 to 512 days, the character of 
the bacillus was not changed (English Commission and Weber), and that bacilli of 
the human type by eight subsequent passages through goats, in 516 days, and l\v four 
passages through cattle in 685 days, were not influenced in their typical characteristics. 

The immunization experiments which were undertaken with the bacillus of the 
human type on cattle showed no changes whatsoever in the human type after the pres- 
ence of the bacteria in cattle for a year and seven months (Baldwin) in spite of their 
])ropagation in the udder of the cow. The same results were obtained in three experi- 
ments by Weber, Titze and Joern, who allowed the bacillus of the human type to exist 
in the body of cattle for two years and one month and for two years and six months. 

Eber 's experiments found no confirmation in the Imperial Board of Health; the 
experiments however are being continued in strict co-operation with Eber. 

On the contrary it is shown that the bovine bacillus constantly 
retains its characteristics within the human body. 

From a boy who was affected since his second year with tuberculosis of the fourth 
digital bone of his hand, it was possible during surgical interference to obtain material 
from the same place at five different times, during his age from 8 to 13 years. The in- 
fection was caused by the bovine bacillus. 

In spite of their existence for ten and a half years in the human body these 
bovine bacilli had retained their characteristics. A marked influence in their virulence 
was manifested, however, since the bacilli, from the second operation, in quantities of 
2 mg. could no longer kill rabbits even after intravenous inoculations. From the sub- 
sequent operations it was found that the virulence was again increased. 

Griffith obtained the same results with bovine cultures from lupus from which the 
bacilli were isolated six months, two and three and a half years, respectively, after the 
first examination. Tt is true that the virulence was several times lower than is or- 
dinarily the case with the bovine type; the other characteristics of the strain however 



Transmission of Bovine Tuberculosis. 105 

were tenaciously retained. In one of the eases the bacillus persisted in the hnman body for 
18% years. Passage through rabbits and cattle again increased its virulence. Al- 
though through animal passage a change of the virulence is possible, nevertheless this 
change results only inside of the borders of the type and in the direction of the type. 
The bovine bacillus therefore does not pass into the human type, nor the latter 
bacillus into the bovine type. 

Only a brief statement will be made relative to the so-called 
atypical strains. It has been demonstrated that there are cultural 
strains which cannot be classified as belonging either to one or the 
other type (Kossel, A¥eber and Heuss, Lydia Eabinowitsch, de 
Jong and others). These strains proved to be mixed cultures of 
both types. In the same person not only mixed infections of both 
types may exist in the affected organs, but also a double infection 
may occur in such a way that in one organ the Typus humamis, and 
in the other organ the Typus hovimis, may be found in pure culture 
(Weber, Weber and Taute, Grriffith, Park and Krumwiede, 
Steffenhagen). 

In 1901 Koch explained at the International Tuberculosis 
Congress at London, that tuberculosis of man is produced by a 
tubercle bacillus which differs from the bovine tubercle bacillus, 
and expressed himself as opposed to the general prevailing opin- 
ion of that time, regarding the great danger of the cattle tubercle 
bacillus for man, and as believing that the transmissibility of 
bovine tuberculosis to man was so slight compared with the dan- 
ger which threatens man from tuberculous human beings, that its 
practical importance was negligible. 

Although Koch's statement cannot stand in the directness of 
his declaration, nevertheless at the present time it is generally 
accepted from the above mentioned differential characters, that 
marked differences exist between the bacillus of bovine tubercu- 
losis and that of man, and it is a fruitless work to dispute whether 
they are differences of varieties or peculiarities of the different 
strains, which lead to the variations, if we accept the fact that the 
differences of the strains are obstinately retained. 

The results are of especial value in differentiating the two 
types of tubercle bacilli. In association with Shtitz, Koch under- 
took some experiments to establish points of differentiation. 

Nineteen calves which were infected intravenously, subcu- 
taneously, intraperitoneally, by inhalation or feeding experiments 
\\ii\ii\iQ BacillKs humamis, showed no manifestations of disease, in- 
creased in weight, and on autopsy conducted several months after 
infection, showed only caseous purulent changes at the point of 
inoculation. On the other hand, after the inoculation of bovine 
tubercle bacilli, severe febrile symptoms and extensive tubercu- 
losis, especially of the lungs, liver and spleen resulted. The same 
results were obtained from the experiments of Kossel, Weber, 
Heuss. Bacilli of the human type were retained in the regional 
lymph glands ; the changes induced by them gradually retrogressed, 
whereas infection with the bovine type of the bacillus led to a pro- 



106 Tuberculosis. 



gressive tuberculosis. Iiilialation and feeding experiments showed 
the slight virulence of the human tubercle bacillus for cattle. 

In the experiments of Nocard, Meyer, Calmette and Guerin 
and Zwick, the inoculation of tubercle bacilli of bovine origin into 
the milk ducts resulted in a tuberculosis of the udder with rapid 
enuiciation of the animal, terminating in death ; whereas the bacilli 
of human origin produced only a passing inflammatory irritation, 
and an interstitial atrophy of the udder. Calves which nursed on 
these latter infected udders remained healthy (Zwick and Maier), 
or on the other hand (in one case of Zwick) intestinal tuberculosis, 
Avitli tuberculosis of the mesenteric lymph glands, developed. At 
autopsy undertaken 20 weeks after the infection, the ndder of the 
cow showed atrophy with miliary tulierculosis, without however 
typical tuberculous changes in the regional lymph glands. 

From these results the conclusion may be drawn that tubercle 
bacilli of human origin are only very slightly dangerous for cat- 
tle. It should be considered however that occasionally after artifi- 
cial infections the bacilli may persist in the infected region, with 
or without marked local or at times even generalized changes. 
Calves may develop intestinal tuberculosis or tuberculosis of the 
mesenteric hnnpli glands as a result of ingesting a large amount of 
tubercle bacilli of the human type. 

Almost the same relation exists in man towards the bacillus 
of bovine tuberculosis. The principal dangers threatening man 
are through the possibility of infection from affected human beings, 
and less so to the possibility of infection with diseased products of 
animal origin, as for instance milk. The possibility of tuberculosis 
infection through animal products is presented with remarkable 
frequency, as may be seen from the above statements; still the 
rarity of infection with the bovine type is quite striking. 

Hogs which become readily infected with the bovine type are very frequently af- 
fected by the ingestion of skimmed milk containing tubercle bacilli. 

In northern Germany some of the herds show an infection of 50-60, occasionally 
even up to 90'/f . The experience at the tuberculosis eradication stations indicated that 
by the elimination of cattle affected with open tuberculosis a marked reduction was 
obtained in tuberculosis of hogs, and that this measure in association with pasteuriza- 
tion of the skimined milk, offers a certain remedy against the spread of tuberculosis of 
hogs. 

The same opportunity which is afforded hogs to contract 
tubercle bacilli from the feeding of skimmed milk, would apply 
to man. The relative infrequency of the infection of man with 
the bovine type of tubercle bacillus is not the result of a milder 
virulence of the bacilli but is due to the previous boiling of the 
milk. Convincing observations have also been made on this point. 

However before entering into a discussion of these, it will be 
advisable to illustrate further the possibility of infection for man 
from the standpoint of the port of entry, and also show the relative 
condition existing between the necessary infective quantity of 
bacteria and the establishment of the disease. 



Insestion Tuberculosis. 107 



The development of the affection depends on the most varied 
conditions, on the quantity of the introduced virus, condition of 
the port of entry, general resistance, etc. 

Frequency of Tuberculous Infection Through the 
Alimentary Tract. 

If the lesser virulence of the bovine type for man, as compared 
to the human type, is left out of consideration, which fact is con- 
sidered satisfactorily proven, the experiments of Ostermann, 
Schroeder and Cotton show what great quantities of infectious ma- 
terial are necessary in order to produce tuberculosis by ingestion. 

Schroeder and Cotton fed milk artificially infected with tuber- 
cle bacilli, and proved that infected milk which invariably produced 
tuberculosis when inoculated intraabdominally in 5 c._ c. doses, 
could be fed for 30 days without causing the disease in the ex- 
perimental animals. 

The dilutions were prepared (1) by adding one platinum loopful of a cloudy sus- 
pension of tubercle bacilli to 10 e. e. of milk. (2) by adding one loopful of the orig- 
inal suspension to 10 c. c. of sterile water, and of this dilution one loopful was placed 
into 10 c. e. of milk, (3) by adding one loopful of the original suspension to 100 c. c. of 
sterile water and of this dilution one loopful was placed into 10 c. c. of milk. It was 
not possible to produce ingestion tuberculosis with either the second or third dilution 
during the period of the experiment, although the dilutions were not as high as they 
occur in the milk of tuberculous animals (with the exception of tuberculosis of the 
udder). 

Ostermann by comparing the average number of tubercle 
bacilli in cow's milk with the minimal dose necessary for producing 
ingestion tuberculosis in guinea pigs, rabbits and goats, came to 
the conclusion that an alimentary infection is exceedingly rare. 

Nevertheless the danger of an alimentary infection with bovine 
tubercle bacilli, even in high dilutions of the tuberculous material 
in market milk, cannot be disregarded. 

The danger of infection to which small children are exposed 
from the ingestion of food (without attempting to distinguish "bo- 
vine tuberculosis" from "human tuberculosis") is best illustrated 
by the clinical cases and also those cases of intestinal and mesen- 
teric tuberculosis which are found on autopsy. 

Edens, from October 1, 1904, to September 30, 1905, found 
12%, and from this time until September 30, 1906, 13.6% of the 
bodies of children which he autopsied at the ages of 1 to 15 years, 
affected with primary intestinal tuberculosis or tuberculosis of 
the mesenteric lymph glands, whereas in man from 15 to 19 years 
of age only 3.8% and 2.6%, respectively (all autopsies), showed 
the disease. 

The intestinal tract of children appears therefore to be a 
prominent port of entry for the tubercle bacillus, which is also 
proven by the works of Orth, Henke, Chiechanowski, Hamburger, 
Nebelthau, Lubarsch, Bruning, Fibiger and Jensen, S;^anes and 
Fischer, Price and Jones, Kingsford, Harbitz, Og-^^da, Edens, 
Wagener and Heller, who demonstrated primary intestinal tuber- 



JOS Tuberculosis, 



culosis in varying proportions, np to 47.6% of the tuberculous 
cliiklren. The frequency, however, with which tu))ercle l)acilli 
actually pass through the intestinal wall without producing demon- 
strable changes in the intestines and mesenteric lymph glands 
cannot be stated. The intestinal tract may be the avenue of 
infection without itself or its regional Ijanpli glands becoming in- 
fected. The percentage given above shouhl therefore be higlier. 
The works of McFadyean, MacConkey, Plarbitz, Weichsell)aum, 
Bartel, Rosenberger, Raljinowitsch, Ipsen and others offer proof 
for this contention, as they mention cases in Avhicli apparently 
healthy mesenteric lymph glands contained tubercle bacilli wliicli 
although ap])earing to be in a latent form at the time of finding, 
])roduced tuberculosis when inoculated into experimental animals. 
It appears also to be proven experimentally that through the 
feeding of tuberculous material tuberculosis of the lungs may 
develop without the presence of intestinal tul)erculosis or tuber- 
culosis of the mesenteric glands (Bartel, Bongert, Kovacs and 
others). In this regard the question may be raised as to whether 
there is any possibility of the tubercle bacilli working up from 
the intestines into the esopha£>iis, and into the buccal cavity, 
from which inhalation tuberculosis could result (Uffenheimer, 
Dieterlen). 

This objection would not enter into consideration for the pur- 
pose of milk control, since it is immaterial for the hygienist work- 
ing along practical lines, whether the infectious agent causes dis- 
ease in the body by way of the circulation or through inhalation. 
In this instance it is only necessary to keep in view preventive 
measures, which should completely prevent the body from com- 
ing in contact with producers of the infection. 

Alimentary Infection of Man With Bovine Tuberculosis. 

After the supposed cases of transmission of the bovine tuber- 
cle bacillus cited in former years failed to withstand critical 
observations, Koch at the International Tuberculosis Conference, 
held in Berlin, in 1902, urged the following up of all cases 
of established tuberculosis of the udder, the determination of how 
long the disease persisted, who consumed the milk and milk pro- 
ducts from these cases, whether the milk had been boiled and 
whether the respective persons became affected with tuberculosis. 

This request was fruitful of results, and in 1910 Weber pub- 
lished the results of his compilation investigations, whicli wore 
carried out by the aid of official statistics from Prussia, Bavaria, 
Saxony, Wurttemberg, Baden and Hessen. 

The investigations extended over the time between the ])e- 
ginning of 1905 to April, 1909; the investigation of some of the 
individual cases however is still being continued, since in the 
chronic courses of tuberculosis it must be considered that the 



Bovine Tuberculosis in Man. 109 



results of infection with bovine tubercle bacilli may under certain 
conditions only manifest themselves after years have elapsed. 

In the given period 113 cases were reported, of which 68 were 
from Prussia, 14 from Bavaria, 6 from Saxony, 6 from Wurttem- 
berg, 10 from Baden, and 9 from Hessen. 

At least 628 persons came under consideration in the inges- 
tion of such milk, possibly even more, since at times only the term 
''family" is designated, and the milk was not infrequently deliv- 
ered to dairies with a large patronage. These cases were not in- 
cluded, although every person is exposed to an infection w^ho par- 
takes of such milk and dairy products. 

In the case of 9 persons no age is given; 284 were children, 
and 385 adults. 

The value of the individual cases must of course be judged 
in different ways. 

In 44 cases it is stated that the milk had been consumed only 
as an addition to coffee, or mixed with milk of healthy animals, or 
the data were otherwise not accurate. 

Of especially great interest are those cases in which it was 
emphasized that the milk was consumed in a raw state, unmixed, 
mixed with milk of only a few cows, or in which such milk was 
used in the preparation of butter, buttermilk, sour milk, or had 
been consumed for a long period. In such cases tremendous num- 
bers of tubercle bacilli must have been taken into the digestive 
tract. According to Bang and Wall the milk from tuberculous 
udders may retain a normal appearance for months, being used 
as food without any objection, and yet such milk contains millions 
of tubercle bacilli. Bang found in smear preparations of such 
milk, in a single field as many as 200 bacilli. 

In all 69 cases were reported, in which it was stated with cer- 
tainty that raw milk of animals with udder tuberculosis, or pro- 
ducts prepared from such milk, were consumed. 

The milk was taken for a longer or shorter time, in large 
quantities, by 151 children, 200 adults, and 9 persons whose age 
was not mentioned. 

These persons are divided by Weber according to the results 
of the investigations, into four groups, namely: 

1.- Cases, in which an infection occurred of a bovine type. 

2. Those in which a suspicion of an infection exists, but 
on account of insufficient bacteriological examinations has not 
yet been determined. 

3. In affections in which the bacteriological examination 
relative to the suspicion of tuberculosis was negative, or in which 
the human type was found exclusively, and 

4. Cases in which no affections whatsoever have been dem- 
onstrated up to the present time. 

In Group 1 an infection with the bovine type was demonstrated 
in two families, affecting one child in each. 



21U TuberriiKisis. 



In both cases it was .possible to trace the consumption of milk 
containing the bacilli up to the nursing age. In one case it lasted 
for one and a half years, in the second case one year, and in the 
latter case the ndder affection had been recognized for three 
months during the period that the child had been using the milk. 

In both cases the respective cow was affected with a severe 
tuberculosis of the udder in all four quarters ; the milk had ])een 
consumed at all times mixed with the milk of a second cow, in the 
first case boiled or raw but in the second case only raw. 

The other members of the family remained well in spite of 
the consumption of this milk; in both instances only the youngest 
child became affected Mitli tuberculosis of the cervical glands. 

In the first case another child of four, and one of five years, 
Avas included in the family; in the second case children of the age 
of 3, 4, 7, 8, 9 and 12 participated in the consumption of the milk, 
all remaining normal. 

The tuberculosis of the cervical glands healed in the two 
youngest after aliscess formations, leaving several slightly en- 
larged small glands in the surrounding parts. One of the boys 
appears to be in the best of health, the other is somewhat behind in 
his development (at the age of 2 34 years he weighs 251bs.) ; in the 
last six weeks however his weight increased slightlv more than 
1 lb. 

In the cases of the second group there exists suspicion of a 
bovine type of infection. 

In six children and one adult there are swellings of the cervi- 
cal Ijmiph glands and in four children and one adult a suspicion 
of abdominal tuberculosis is given. One child is affected with 
scrofula. In the four children the manifestations of disease re- 
trogressed, while in the adult it appears doubtful, according to 
Weber, whether the affection is of a tuberculous nature. 

Forty-one persons are included in Group 3, who consumed 
milk in a raw state from cows affected with tuberculosis of the 
udder. This was at times mixed with milk of other cows. A girl of 
16 years of age and a boy four years old, who died of tuberculosis 
were included in this group. The producers of their infections 
were bacilli of the human type. A man and a woman who were 
affected A^^th pulmonary tuberculosis (human type), a boy with 
suppuration of the middle ear and cervical haupli glands (not 
tubercular) ; an 18-year old boy Avith rheumatism of the joints 
and valvular heart trouble, chronic diarrhea and pulmonary symp- 
toms (not tubercular) ; a woman with catarrh of the apex of the 
lungs (not tubercular) ; a woman with swelling of the glands, 
diarrhea, cough, night sweats and emaciation (inoculation of 
sputum without results), and a woman and a man with pulmonary 
SAnnptoms (not tubercular) were also in the total of forty-one. _ 

The cases in which a boy and a girl died from tuberculosis, 
are of especial importance. In spite of the prolonged consump- 



Table III. 



tr 










<- 



k 

At- ^ 



V? k from a rabereaiC'Bs adder. 1 X 1200. 



fy'it if-'i- Wi 



Danger from Boviiie Tuberculosis. ]_11 

tion of raw milk from a tuberculous udder by tlie children who 
were already infected with the himian type of the disease, it was 
impossible to isolate from the tuberculous glands of the neck and 
mesentery any bacilli of the bovine type. Weber concludes from 
this that a body already infected with the human type of the dis- 
ease is resistant rather than susceptible towards an infection with 
the bovine type. 

The fourth group contains by far the greatest number of 
cases in which children and adults consumed raw milk from cows 
affected with tuberculosis of the udder, or milk products prepared 
from the same, and includes those cases in which no disturbances 
of the health resulted from such consumption. It was especially 
stated relative to the children that they all appeared thriving and 
healthy. Among these persons are included those who for a long 
period ingested especially great quantities of bovine tubercle ba- 
cilli ; thus a 13-montli old child has been brought up exclusively on 
raw and boiled milk from a cow affected with udder tuberculosis, 
and up to the present remains healthy. 

Other cases may be considered as presenting complete ex- 
periments with the necessary controls, since the persons who 
drank the milk remained healthy, whereas calves and hogs fed with 
the same milk developed severe ingestion tuberculosis. The ob- 
servations of such cases may be traced back incompletely for 
3 or 4 years. 

A 25-year old waitress, and a 28-year old dairy hand drank mugfuls of freshly 
drawn tuberculous milk, frequently without any other milk being added without be- 
coming affected; the calf of the cow which produced the milk had to be slaughtered 
after four weeks, and showed tuberculosis of the mesenteric lymph glands, liver, lungs 
and kidneys, a severe ingestion tuberculosis. 

The milk of another highly affected tuberculous cow also suffering from udder 
tuberculosis, was mixed with the milk of two other cows, and was consumed frequently 
in a raw condition, by two adults and a 13-year child; a child l^/^ years of age was 
given the milk only in a boiled condition. The adults remained healthy; the calf from 
this cow had to be slaughtered after five weeks, and showed generalized tuberculosis. 

From the stable of a herdsman the milk of a cow affected with udder tuberculosis 
was mixed with the milk of three other cows, and the cream and butter prepared from 
this was consumed by four persons, aged 31 to 59 years, without producing any ill 
effects. The five hogs of the herdsman were found on postmortem to be tuberculous. 

Similar results were reported from the ingestion of milk from a tuberculous udder 
of a goat, which was consumed as raw and boiled milk by three adults and four chil- 
dren of ages from 5 to 16 years. The persons remained well while a hog became af- 
fected with ingestion tuberculosis. 

In two other cases the milk was consumed in a raw or unmixed state, as milk, 
buttermilk and butter. It was consumed by seven adults, in one case for a period of 
four months, in another case even longer. In spite of the fact that the family has been 
kept under observation for four years no disturbance in health can be detected. 

It is proven by the collected material of Weber that even 
though tremendous quantities of tuberculous material are con- 
sumed, still more favoring accessory conditions are necessary in 
order to produce an infection with the bovine type of tubercle 
bacilli. Of course it is not yet known, as indicated by Weber, how 
many of the children which show swelling of the cervical lymph 
glands and symptoms of suspected abdominal tuberculosis, are 



X^'2 Tuberculosis. 



affected with the bovine type of tul)erculosis, or how many of the 
persons who fail to show any distnr})ance of health may harbor 
one or more infected mesenteric glands ; likewise it is not known 
how many children with a latent form of the disease may through 
a special weakening, or nnder the influence of other infections, 
break down later with tuberculosis, possibly even with a fatal 
termination. 

Tlirough the compilation investigations we know only of the 
time (which extends over a period of 1-3-4 years in the individual 
cases), the opportunity and the immediate results of the infection, 
and not the further development of the same, but we do know that 
in two children a true bovine type of tuberculosis existed. 

Therefore, although a possibility of infection was present in 
a great number of persons, the infection has positivel}^ occurred 
up to the present only in two children in infancy. This constitutes 
proof that ''the danger which threatens man from the consumption 
of milk and milk products from cows affected with udder tubercu- 
losis is very slight when compared with the danger of man affected 
with open pulmonary tuberculosis to his fellow men." 

This conclusion of AYeber may be supported without further 
consideration. Nevertheless the danger still prevails, and al- 
though it is slight in comparison with the danger through infec- 
tion with the human type, it should he hj no means under-esti- 
mated; it should be considered that the danger of infection with 
human tuberculosis is amazingly great, and the opportunity of 
ingesting the bovine type of tubercle bacillus with milk is similarly 
great. 

Bovine Tuberculosis in Man in General. 

Although the attention of pathologists of all countries has 
been directed for the last ten years to infections of man with bovine 
tuberculosis, up to the present time there are collected only 117 cer- 
tain cases of bovine tuberculosis in children and 21 cases in adults 
(over 16 years of age). 

Of the 117 cases in grown children 105 are accurately de- 
scribed, and involve the following organs : 
60 cases of abdominal tuberculosis 
25 cases of tuberculosis of the cervical glands 
4 cases of tuberculosis of the tonsils 
7 cases were generalized 

3 cases were localized in the bones and joints 
6 cases represented lupus 
Two cases should also be included in which bovine bacilli were 
found in unchanged lymph glands. 

The 60 cases of abdominal tuberculosis are again divided into 
34 severe cases in which the mesenteric l^miph glands, the intes- 
tines and the peritoneum showed changes. Thirty of these after 
generalization of the afl'ection, terminated in death. 



Bovine Tuberculosis in Man. 113 



Twelve of the 60 patients had tuberculosis of the mesenteric 
glands, slight intestinal tuberculosis, and tuberculous meningitis. 
The 12 cases were severe fatal affections. 

In 14 cases the autopsy revealed tuberculosis of the mesen- 
teric lymph glands with the bovine tjY>e of bacilli, but this was 
found accidentally following other causes of death, as diphtheria, 
scarlet fever, measles, and pneumonia. 

In the 21 adults the bovine type of the disease was established 
three times in pulmonary tuberculosis ^vith expectorations, once 
in a primary abdominal tuberculosis and pulmonary tuberculosis, 
once in an infection of the buccal mucous membrane and cervical 
lymph glands, once each in tuberculosis of the knee joints, the kid- 
neys and the peritoneum, and finally the bacillus of bovine type 
was isolated from three cases of lupus, two cases of skin tuber- 
culosis, and five cases of tuberculosis verrucosa cutis in butchers. 
Besides these instances the bovine type of tubercle bacillus was 
isolated three times from the mesenteric glands of adults. 

In two cases of phthisis the bovine tubercle bacillus was found 
in association with the human type. 

Of the total of 138 cases, 56 were fatal, and 89 could be ex- 
plained with certainty or Avith the greatest probability as inges- 
tion tuberculosis. The other forms of tuberculosis, v^th the ex- 
ception of the skin tuberculosis of the butchers and of one milker, 
may also probably be traced to the same mode of infection. 

AYeber deduces from his findings that the danger of becoming 
infected with tubercle bacilli of cattle is great for the individual, 
but is only slight for the human race as a whole. 

Kossel reports in the German Medical Weekly relative to the 
number of cases of animal tuberculosis in man as compared with 
the human type of tuberculosis, and observed that in 1602 cases 
of human tuberculosis the bovine type appeared as the infective 
agent in 126 cases, the human type alone in 1464 cases, the human 
and bovine type in association nine times, and the a^^an type of 
tubercle bacillus three times. Therefore in about 8.6% of human 
tuberculosis, bacilli of animal origin were found, and in about S% 
of these they were of the bovine character. If however the most 
frequent form of tuberculosis of man is considered, namely pul- 
monary tuberculosis, then the bovine type can be demonstrated 
only in about .6% of the cases, whereas in the other forms of 
tuberculosis it may be found in 16% of the cases. 

Tuberculosis of bovine origin occurs most frequently in chil- 
dren in which tuberculosis of the cervical glands is caused in about 
40% of the cases from infections with the bovine tAT)e, and tuber- 
culosis of the mensenteric glands may be traced to the same type in 
40 to 50% of the cases. A portion of these affections, as has al- 
ready been mentioned, may terminate fatally. Among the fatal 
forms of tuberculosis in children 76% are caused by the human 
type and 24% by the bovine form. The meningitis type of the 
s 



214 Tuberculosis. 



disease is brought on in "only about 11 7o of the cases by the bacil- 
lus of animal origin and in 89% by the human type of tlie organism. 

In tuberculosis of the bones and joints the iigures are 57© 
and 95% respectively. 

Galf ky, Rothe and Ungermann found in 400 bodies of children, 
76 infections with tuberculosis, in which tliej^ succeeded in estab- 
lishing the variety of the bacillus. In one case they found the 
bovine type (1.32%), and among 171 other autopsies on children, 
of which 39 were tuberculous, two (5.1%) cases of bovine infection 
were observed. 

The results of tuberculous infections among children of the 
population of Berlin were therefore 95 to 96% of human origin, 
while only 4 to 5 % were of bovine origin, in spite of the fact 
that during infancy the danger of bovine infection is the greatest 
(Kossel). 

[According to figures compiled by Park of the New York 
City Board of Health, the frequency of bovine tuberculosis in man 
as collected by various investigators is as follows : 

In adults, 955 cases have been examined of which 940 showed 
human infection and 15 bovine infection. In children from five 
to sixteen years of age, out of 177 cases investigated, 131 were 
human infections and 46 bovine infections. Among children under 
five years old there were 368 cases of which 292 were found in- 
fected with the human type and 76 with the bovine type of tuber- 
culosis. Furthermore Park mentions the very suggestive results 
obtained from nine children under 6 years of age who were fed 
exclusively on cow's milk at the Foundlings' Hospital. Five of 
these children died of bovine infection and four of human infec- 
tion. On the other hand in the Babies' Hospital where the infants 
are nursed or fed on prescription milk, out of 63 children dying 
of tuberculosis, 59 proved to be human infection and 4 bovine 
infection. 

The figures taken from clinical work in England indicate that 
from 23 to 25% of the fatal cases of tuberculosis in children are 
due to bovine infections. Stiles of Edinburgh has presented in- 
teresting statistics to illustrate how bovine tulDcrculosis particular- 
ly affects young children. Of 67 consecutive tuberculous bone and 
joint cases, the bovine bacillus was present in 41, the human bacil- 
lus in 23, while in 3 cases both types were present. In those af- 
fected children under 12 months old, only the bovine bacillus was 
found. Of the 12 children between 1 and 2 years of age, 8 owed 
their disease to bovine infection, 2 to human infection and 2 to 
both bovine and human infection. There were 15 cases in 2 to 3 
year old children, 11 of which were bovine, 3 human and 1 both 
infections. The 10 cases from the 3 to 4 year period were 6 bovine 
and 4 human infections, while the 4 to 5 year period included 3 
cases of each type of infection. Stiles further reports on 72 cases 
of tuberculous cervical glands operated on at the Children's Hospi- 



Control of Bovine Tuberculosis. 115 

tal in Edinburgh, in which the disease was due to the bovine bacil- 
lus in 65 cases, while in only 7 patients was the disease caused by 
the human bacillus. — Trans.] 

Conclusions. 

If we compile the results of this chapter the following conclu- 
sions may be established: 

Although tuberculosis of cattle is less dangerous for man than 
tuberculosis of man, the danger from the enormous spread of the 
disease in our herds, and especially among the dairy cows, should 
in no way be under-estimated. Theoretically the possibility of 
infection is afforded in all cases in which the ingestion of living 
tubercle bacilli with the milk takes place; from a practical stand- 
point however this possibility of infection comes into consideration 
only when the bacilli enter the individual in great quantities, and 
the resistance (of a local or general nature) of the body is not 
equal to this quantitative attack. This disposition, or these rela- 
tive conditions between the injurious agents and resistance, appear 
to be especially unfavorable in children ; therefore the requirement 
of the elimination from dairy herds of all tuberculous animals 
which pass tubercle bacilli with their milk, appears to follow as a 
matter of course. According to the experience at the tuberculosis 
eradication stations only those animals must be considered as 
eliminators of tubercle bacilli which are affected with open tuber- 
culosis, and expel the tubercle bacilli with their secretions and 
excretions, especially animals affected with tuberculosis of the 
udder, open pulmonary tuberculosis, tuberculosis of the uterus, 
intestinal tuberculosis, and furthermore animals with tuberculosis 
of the liver, kidneys, skin, eyes, and larynx. 

Measures Against the Danger. 

The elimination of animals passing tubercle bacilli should 
also be energetically encouraged on general economic grounds. 
For this work three methods may be followed : 

1. Treatment of the disease and curative attempts. 

2. The immunization of healthy herds. 

3. Energetic sanitary police eradication measures, reduction 
of the possibilities of infection, and protection of young animals 
from- infection, together with favorable conditions for bringing 
up young stock as a preventive measure against their accidental 
infection, toward which we are powerless. 

The curative measures in affected animals may be left out of 
consideration as measures of control, since — excepting the uni- 
formly bad or only slightly favorable results — the methods of 
treatment for veterinary practice are too complicated, and are 
not practicable in consideration of the value of the animal. For 
the sake of completeness the experiments with iodipin should be 
mentioned here (Hauptmann). Creosote has also been employed. 



1]() Tuberculosis. 



Of the specific remedies, tuberculin, tulase, tulase-lactin, 
tulon and tnberculase could be considered in the treatment of 
affected animals. These bacterial preparations, however, accord- 
ing to Romer and Arloing, are ineffective, since the results were 
negative. 

Better results Avere promised at the onset, from the specific 
innnunization methods, which aimed at a systematic preliminary 
treatment with slightly virulent strains, or with attenuated bovine 
tubercle bacilli, to increase artificially the resistance of the im- 
munized animals, that is, to protect them against a later accidental 
natural infection. As a matter of fact cattle immunized with 
tubercle bacilli prove for a time to be immune, or at least manifest 
a considerable resistance against a subsequent artificial infection 
with bovine tubercle bacilli, when compared with non-immunized 
control animals. For innnunization purposes there have been 
used : 

1. Dry tubercle bacilli of the human type (bovo-vaccine. Von 
Behring's method). The injection is made into the blood circula- 
tion and is repeated. Animals treated in tliis way after 3 to 4 
months, resist an intravenous injection of bovine tubercle bacilli, 
to which untreated animals invariably succumb. This increased 
resistance however lasts only a short time. According to the in- 
vestigations of Rossignol and Yallee and Hutyra it diminishes to- 
M'ards the end of a year, and after another six months it practically 
disappears. Against the slight practical success of this method 
the disagreeable fact should be considered that the injected tubercle 
bacilli of luan are retained alive in the body of the cattle for years, 
and may even produce in the udder local tuberculous processes, 
from which the bacteria of human tuberculosis may enter into the 
milk (Lignieres, Weber and Titze). 

Titze found that following an intravenous injection of human tubercle bacilli, 
they were eliminated from the udder even 16 months after the injection. In this regard 
the various individuals manifest an entirely different behavior. In three other cases 
bacteria were eliminated after a single injection, from the fourth week up to the 144th 
day. In a second cow which received an injection of tubercle bacilli of human and 
bovine type the elimination commenced after the third injection, and in a third cow as 
early as 24 hours after the injection. All three animals eliminated the bacilli from only one 
quarter, without this showing tuberculous changes. 

Bongert found in 186 bovo-vaecinated cattle, 36 which passed tubercle bacilli 
with their milk. 

The protective vaccination of Von Behring therefore is not 
only of little practical value, but grave dangers must be considered 
in connection with it, since the vaccinated animal may eliminate 
tubercle bacilli with the milk for 21/0 years and longer. 

Koch and Schiitz, Neufeld and Miessner recommended for the 
immunization of cattle a single injection of 0.01 gm. tubercle 
bacilli in suspension, which vaccine they termed ''tauruman." The 
above statement applies equally for tauruman as it does for 
bovo-vaccine. Similar results to the immunizing value of the in- 
travenous injections, according to Baumgarten, Lignieres and 



Tuberculosis Vaccination. 117 



Klimmer may be derived from the single subcutaneous admin- 
istration of human tubercle bacilli. According to Lignieres even 
in such cases the bacteria may remain alive for as long as two 
years. 

According to Von Behring, Calmette and Gnerin, Eoux and Vallee, cattle may 
become immunized by feeding with slight quantities of bacilli from tuberculosis of 
the horse (or bovine tuberculosis). 

Arloing attempted to immunize with homogenized cultures of strains which had 
been cultivated in 6% glycerine bouillon (human type and bovine type). Better results 
were obtained from the intravenous than from the subcutaneous applications and this 
again proved superior to administration per os. 

Klimmer eliminated the danger of the vaccination for man by 
heating the human tubercle bacilli to 52-53 deg. C, or by rendering 
them avirulent by continuous passages through the crested newt. 
Both these vaccines are no longer pathogenic for guinea pigs, and 
they cannot regain their virulence by means of passages through 
animals. The results of immunizations are supposed to be favora- 
ble (Klimmer on 10,000 cattle), especially if the vaccination is 
carried out together with general protective measures, such as 
raising calves on milk free of tuberculosis, and the elimination of 
animals with open tuberculosis. Glockner even believes that vac- 
cination has a favorable action on the curing of animals which were 
already affected with bovine tuberculosis prior to the vaccination, 
whereas Eber attributes the improvement of the vaccinated herds 
to the simultaneously executed prophylactic and hygienic meas- 
ures. Friedmann aimed to produce immunization with his tuber- 
cle bacillus from cold blooded animals (turtle). Other authors 
however failed in producing an effective immunization with such 
strains (Libbertz and Ruppel, Weber and Titze, Orth). 

Heymanns attempted to immunize cattle by the introduction 
under the skin of cattle of a closed sack of vegetable fiber, contain- 
ing living tubercle bacilli (human or bovine in origin). The sup- 
position is that these vegetable sacks will confine the bacilli at the 
seat of inoculation, and that the treated animal will be immunized 
by protective metabolic products, that continuously form in small 
quantities within the sack and pass outward from it into the 
animal's system generally, by an osmotic process. 

The vaccination, which is carried out with the aid of a tro- 
car to insert the capsule under the skin of the back, must be re- 
peated annually, since the bacilli may die. 

Ueymann's method has been successfully used by its discov- 
erer on more than 20,000 cattle, and the percentage of reactors 
to the tuberculin test diminished from 45 to 21 (18 herds with 188 
animals). Animals which have formerly reacted may appear free 
at the subsequent test. 

Good results were obtained by Vallee from passive immuniza- 
tion. He inoculated young cattle with 100 to 200 c. c. of a protec- 
tive serum, which he obtained from a horse treated with slightly 
virulent strains from horses, and then with strains from men. 



][28 Tuberculosis. 



With this method he succeeded in rendering- the animals resistant 
to artificial infection with bovine tnbercle l)acilli. 

Since immunization methods have not offered nniformly 
satisfactory results, and since they must be prohibited on the 
ground of milk hy.<>ieno, therefore results may be expected only 
from proved sanitary police measures. 

Tlie methods which must be followed in the eradication of 
bovine tul)erculosis are: 

1. Diminution or elimination of the sources of infection, 

(a) By removal of the animals passing bacilli, 

(b) By separation of healthy and suspected or diseased 

animals, 

(c) By l)ringing np tuberculosis-free yonng animals. 

2. Improvement of the general methods in the care of young 
stock, l)y introducing conditions which approach the natural mode 
of living: 

(a) Proper care and feeding in well ventilated and lighted 

stal)les, 

(b) Dividing tlie pastures so- that the animals may be sepa- 
rated (according to whether they are suspected or healthy) and 
kept in accordance with their age and with the nse for which they 
are later intended. 

Measures for eradication must be applied in accordance with 
the rules here outlined. 

The most effective method of eradication was worked out by 
Bang", and consists in the elimination of clinically recognizable dis- 
eased animals, the separation of reacting animals, and the bringing 
up of calves on milk free of tubercle bacilli. 

The remarkable value of Bang's methods has been proven fully 
in practice by the results obtained since 1892. 

It is important for the results to separate completely the 
animals which fail to react to tuberculin, that is the healthy cattle, 
from those which harbor the disease and which react to the tuber- 
culin test. This should be done in such a way that the healthy 
animals are placed in a freshly disinfected stable or in a portion 
of a stable provided with a separate entrance, and separated with 
a board wall, from that part in which the reacting cattle are housed. 
The attendants of the healthy herd should not come in contact with 
those of the diseased herd. Animals of the reacting group which 
after a time become affected so that they may be clinically recog- 
nized, should be slaughtered as soon as possible. 

Young stock which react should not be permitted to breed, or 
at least should he immediately placed with the reacting group, 
providing their breeding value is such that this procedure is 
deemed advisalile. All reacting animals under six months of age 
should be slaughtered, that is they should be utilized for meat. 

Young stock and work oxen should also l)e included in the 



*& 



Methods of Eradication. 119 



segregation, and the liealthy ones must be kept from contact witli 
reacting animals. 

Of the calves which are born after the separation, those from 
non-reacting cows remain with their mothers; the calves from 
reacting cows, after receiving the colostrum from their mother on 
the first day after birth, should be placed in the stable of healthy 
animals, and should be fed with the milk of healthy cows or should 
be brought up on sterilized milk, or they may be allowed to suck 
from healthy nurse cows. As soon as possible after weaning the 
calves should also be subjected to the tuberculin test, and those giv- 
ing a reaction should be immediately removed. From 1 to 2% 
of these calves react. 

It is proper to place the healthy calves in a stable of healthy 
young stock, and they may pasture with them, or if this is not pos- 
sible they should be placed with the older non-reacting group of 
animals. Before the first breeding the heifers again should be 
subjected to the tuberculin test, in order to place them in the prop- 
er group of cows. 

The tuberculin test is annually repeated in the healthy herd, 
in order to eliminate the animals which in the course of the year 
have had a possible opportunity of becoming affected with 
tuberculosis. 

Newly purchased animals are clinically examined and tested 
with tuberculin, and are added to the healthy herd only when the 
results are entirely satisfactory. 

The male animals which are to be used for breeding purposes 
should not react to the tuberculin test. Under unavoidable cir- 
cumstances, a reacting bull may be reserved for breeding pur- 
poses but only under special precautionary measures. 

The results of Bang's eradication method, if carefully carried 
out, are remarkably satisfactory. 

It has been adopted to the greatest extent in Denmark, Sweden 
and Norway, and it has also been successfully carried out in Hun- 
gary and Finland. 

The report of Regner, in 1911, atfords a good review of the 
results of Bang's method, and in it are described the results of the 
governmental eradication of tuberculosis in Sweden. Regner di- 
vides the eradication work into an offensive one in herds in which 
the disease prevails, and into a defensive procedure whose purpose 
is the prevention of the introduction of diseased animals into herds 
free of tuberculosis. 

Of the groups into which Regner separates the herds and the 
animals, the first group includes those which originally (on the 
first tuberculin test which in some instances was applied years 
previously) were found tuberculous. At that time 16,852 animals 
had been tested with a percentage of 30 . 2 reactors. In 1908, 18,719 
animals in 457 herds proved to be entirely free from tuberculosis. 

The herds of the second group, which proved to be tuberculous 



][0Q Tuberculosis. 



at the time of the inaiigiiratioii of the method and which continued 
to contain reacting animals, inchided 375 herds of 21,899 animals, 
with 41.57p of reactors. At the end of 1908 the nmiiber of cattle 
had increased to 26,181, of which only 1,496, or 5.7% reacted. 

The results were not so pronounced when the reacting animals 
were retained with the healthy animals, when cattle without the 
necessary precautionary measures were placed in herds free of 
tuberculosis, when animals which had not reacted in the old herd 
were removed into the free herd without being previously tested, 
or when an opportunity was given for the transmission of the in- 
fection by a reacting bull causing the infection in the herd to ap- 
pear to be renewed. Also in cases when the milk used for the feed- 
ing of calves was not free from tubercle bacilli, the results were 
unsatisfactory. 

In the interest of systematic eradication, it is necessary, espe- 
cially at the commencement of the eradication work, to suliject the 
animals to the tul)erculin test quite frequently, with short intervals. 

As a third group Regner included 436 herds containing 7,835 
animals at the beginning of the work and 9,114 cattle in 1908, 
which at the first examination, and again in 1908 were free from 
reacting animals. 

The fourth group contains the herds which originally were 
free from tuberculosis but were not so at the test in 1908. The 98 
herds included at first 2,526 and in 1908, 3,720 animals, of which 
265 or 7.1% reacted. 

Eegner concludes from his tabulations : that on the first tuber- 
culin test in 1366 herds, out of 49,112 animals tested, 14,175 or 
28.9% reacted; that in 1909 the same herds contained 57,734 ani- 
mals, of which 1761, or 3.1% reacted; that Bang's method is the 
strongest factor in the general promotion of breeding, and of 
stable and milk hygiene. 

In other countries the results were similarly favorable. 

Bang succeeded in Denmark, from 1893 to 1908, in gradually 
reducing the percentage of reacting animals from 40 to 8 . 5. Malm 
in Norway from 1896 to 1903 reduced the disease from 8.4 to 
4.9%). Hojer in Finland in 1894 to 1900 caused the infection to 
drop from 24 to 10.1%. 

Hutyra reports on experiments carried out on the government 
farm of Mezohegyes. In this herd the first tuberculin test in 1 898 
showed 44.8% of reactors out of 329 cows or 26.6% of the entire 
herd (647 animals), whereas in the fall of 1903 out of 502 cows only 
2.8%, and out of the total of 1,132 animals only 1.8% reacted to the 
tuberculin test. The herd had been increased in this period by 
75%, without purchasing additions to it, and the percentage of 
reactions had dropped 88%. 

The stringent measures of Bang have been somewhat modi- 
fied in certain cases for economic reasons, or when the strict execu- 
tion of Bang's method has presented peculiar difficulties. On the 



Ostertag's Method. 121 



other hand the requirements have been accentuated in cases where 
favorable considerations prevailed. Thus for instance in a herd in 
which only a few animals react it would be advisable to dispose of 
them without further consideration, and after a thorough disinfec- 
tion of the stable the defensive work against tuberculosis may be 
instituted, through the introduction of only non-reacting cattle, 
and by the disposing of all animals which prove tuberculous on 
the following tuberculin tests. 

The Siedamg-rotzky-Ostertag method consists of immediate 
disposition of all animals with open tuberculosis (by this means 
the animals eliminating tubercle bacilli are excluded), and in 
bringing up the calves free of tuberculosis by feeding them with 
pasteurized milk or with milk from healthy cows. The calves are 
subjected to the tuberculin test after they are weaned, and the re- 
acting animals are not bred. The herds which are included in this 
method of eradication are subjected semi-annually to a clinical 
examination, and the clinically suspected animals are removed and 
disposed of. Further than this, the mixed milk of the herd, as well 
as the suspicious secretions and excretions are examined 
bacteriologically. 

The results of the Ostertag eradication method of course can 
not be compared v/ith that of Bang. Since there are retained in 
the herd all tuberculous animals which show no clinical form of 
tuberculosis, or in which there is a suspicion of open tuberculosis 
but whose secretions and excretions fail to reveal the presence of 
tubercle bacilli. Therefore a constant danger of infection for the 
animals free of the disease prevails, as tuberculosis may at any 
time develop into an open form. But since it is required that the 
calves should be brought up free of tuberculosis, and that the elim- 
inators of tubercle bacilli should be determined by periodical clin- 
ical examinations as well as by the testing of the entire mixed milk 
of the herd and the individual secretions and excretions of sus- 
pected animals, Ostertag has obtained relatively very good results, 
where his requirements have been conscientiously carried out. 

This method has an advantage in that the stock owners who 
offer great objections to radical methods of eradication on ac- 
count of the immediate economic losses which they entail, are will- 
ing to work intelligently and with pleasure with a system of eradi- 
cation such as is offered by Ostertag's method. 

This assertion is best proven by the tabulation of Eautmann, which shows the in- 
creasing popularity of this method. The method was voluntarily adopted in the fol- 
lowing cases: 

1903-1904, 1,457 animals; 1904-1905, 1,372; 1905-1906, 5,333; 1906-1907, 5,395; 
1907-1908, 5.193; 1908-1909, 8,839; 1909-1910, 18,822; and 1910-1911, 19,828 animals. 
The following data illustrate the results obtained with the method : 
Open tuberculosis was present in the province of: 

East Prussia in 1900 in 2.7 % out of 10900 examinations 

East Prussia in 1904 in 1.3 % out of 17500 examinations 

Pommerania ; in 1902 in 2.93% out of 8808 examinations 

Pommerania in 1906 in 0.6 % out of 22356 examinations 

Brandenburg in 1903 in 3.46% out of 5200 examinations 



] 22 Tuberculosis. 



Braiiilojibiiry; in 1907 in 1.5 % out of 5810 examinations 

Schloswifj-IIolstein in 1903 in 2.8 % out of 2435 examinations 

Schleswig-Holstein in 1905-6 in 1.93% out of 11000 examinations 

Saxony in 1903 in 3.6 % out of 1457 examinations 

Saxony in 1906-7 in 2.41% out of 5395 examinations 

In these statistics it should be eonsi<lere(l that every year new, unexamined herds 

have been included, and further that the experts continually oraineil more skill in making 

the examination. 

A proof of the reduction of the dangerous forms of tuber- 
culosis is first of all indicated ])y the above figures, and also by the 
marked reduction of tuberculosis of hogs. Thus for instance ac- 
cording to Stier the percentage of tuberculous creamery liogs which 
amounted to 40% was reduced to 4% after the eUmination of six 
cattle with tuberculosis of the udder, although none of the 
skimmed milk fed to the hogs had been sterilized. 

In 1907 out of 38,45-1: animals examined in Schleswig, 1.4% 
were found to l)e affected with pulmonary and udder tuberculosis. 
Udder tuberculosis alone was demonstrated in 0.124%. In spite 
of the great advantages of the method, the results eventually come 
to a standstill, as may l)e seen from the more recent reports of the 
eradication stations. The num])er of the dangerous forms cannot 
be reduced below a certain percentage, since latent forms contin- 
uously change into the dangerous forms, and it is therefore im- 
possible to eliminate the sources of infection from the herds. 

The method of Ujhelyi also deserves mention. In this method the cattle are divided 
into a healthy herd and those which react to tuberculin. The newly born animals of 
the grou]) givino- a positive tuberculin reaction are allowed to remain only in emergency 
cases with the reacting mothers, but if possible they are nursed by healthy cows. 

After weaning the calves are tested with tuberculin. This method differs from 
Bang's method only in that sterilized milk is not used (prevention of calf diarrhea) and 
further the calves are allowed at times to remain with the reacting cows. According to 
Ujhelyi's report this method has given irreproachable results. It has to be considered 
however that of the weaned calves a greater proportion of animals must be eliminated 
when this method is employed, than when Bang's method is followed. 

Before the introiluetion of Ujhelyi's method, out of 1,031 adult cattle, 884, or 
85.7% reacted. Out of 626 young stock 333, or 53.2% reacted. After a perioil of 
eradication for 41^ years TTjhelyi succeeded in reducing the infection to 4.1% among 
the adults, and 2.6% "in the young stock. He succeeded in the periods from 1898 to 1902, 
and from 1904 to 1905, in reducing the number of positive reactions among 1,715 cattle, 
of eight state farms, from 59% to 3%. 

The eradication of tuberculosis has been subjected to official 
control for several years in Denmark, Sweden, Norway and Fin- 
land. Thus Denmark in 1893 contributed $13,500.00, later $27,- 
000.00 towards the eradication of tuberculosis, furnished the tuber- 
culin free of charge at first for young animals, later for adults, and 
finally since 1898 took upon itself the total expenses of eradication 
(Hutyra). The skimmed milk is permitted to be returned from 
the creameries to the stock owners only after being heated to 80 
deg. C. Cows affected with tuberculosis of the udder are destroyed, 
the owners being reimbursed. There are about 600 such animals 
paid for annually. 

Similar results were obtained in Sweden, which adopted legis- 
lative measures and made a contribution of $225,000.00. In the 



Results of Control Work. 123 

years from 1897 to 1908 in 1,370 herds with 48,576 animals, of 
which 14,225 or 29.3% reacted, the amount of infection was re- 
duced by their work of eradication to such an extent that out of 
57,660 cattle only 3.1%, that is 1,765 animals, reacted. 

Although the statistics of individual countries having strict 
measures of eradication (Denmark, Sweden, etc.) appear to show 
the splendid effects of carefully executed control work, based on 
scientific principles, and in spite of the fact that the milder modifi- 
cations, as for instance that of Ostertag, by no means show the 
same good results, nevertheless measures of too strict requirements 
cannot be absolutely approved. 

Thus for instance Belgium in 1895 required the destruction within a certain time 
of all clinically affected and all reacting animals, and in 1896 out of 19,004 cattle 
examined 9,280 were slaughtered. The difficulty of the execution was lessened by the 
law of 1897 which required that only the visibly affected animals should be destroyed, 
a measure which resulted in the destruction of 10,269 cattle with reimbursement 
amounting to $300,000.00, in 1902 (Hutyra and Marek). 

Theoretically, the most radical eradication measures may pos- 
sibly be considered as the quickest and most effective, and therefore 
from an economic standpoint as the best methods for the control 
of tuberculosis. Owing to the extraordinary spread of this dis- 
ease in almost all herds, drastic measures however may result in 
the sudden infliction of such heavy economic losses, not alone 
through the animals destroyed, but through changes of values for 
breeding, dairy purposes, meat production, etc., that the stock 
owners, dealers, consumers, etc., would have good grounds to pro- 
test against the execution of such methods. 

Therefore it is advisable to adopt Ostertag 's method at the ini- 
tiation of the general work of eradication, and after the stock own- 
ers have been convinced that the idea is rational following the 
favorable practical results obtained, then Bang's method may be 
introduced, unless it is possible to persuade them to employ, at the 
beginning, the rational execution of Bang's method. In no instance 
however should destruction of the reacting animals be required 
in connection with Bang's method. From the standpoint of milk 
hygiene it does not seem to be justifiable, according to the present 
status of the question of the infectiousness of the milk of reacting 
animals, to require their exclusion from the production of milk, 
unless they show clinical evidence of the disease. 

.In spite of the separation of the reacting from the non-react- 
ing animals, the milk of the reacting group could be marketed, 
from the standpoint of milk hygiene, with the milk of the other 
group, without interference, as has been previously practiced, so 
long as there is no substantial proof offered as to the danger of 
marketing such milk. 

With the new law on diseases of animals the initiation of 
eradication, based on uniform legislative measures, has been in- 
stituted in Germany, and thereby serves as a stimulus to extensive 
private activity in matters of eradication. 



\-24: Tuberculosis. 



The law requires that cliiiically affected tuberculous animals, 
or those in which tuberculosis probably exists to a great extent, 
may be ordered destroyed by the police authorities. 

If this is not carried out, or if the destruction is postponed, 
sanitary police protective measures should be inaugurated against 
further spread of the disease, by branding the animals. 

The police measures against the spread of the disease con- 
sist in separation, observation of police control of the affected, sus- 
pected and susceptible animals ; if necessary restriction of traffic 
of botli man and animals, and special limitations relative to the use 
of affected or suspected animals, and their carcasses, and finally the 
usual requirements of disinfection. 

For animals which are destroyed by the requirements of the 
police, and those which after destruction has been ordered, die of 
the disease on account of which they had been ordered destroyed, 
the government allows corresponding reimbursement. 

Of great importance in tuberculosis eradication is the require- 
ment prohibiting the return of skimmed milk and other milk residue 
to the milk producers, as food for other animals, unless the same 
has been heated. 

This clause is included in the general requirements of the 
measure. Centrifugal slime, which has formerly caused the 
development of ingestion tuberculosis in hogs, must be destroyed 
by burning or burying. 

The measures differentiate three danger classes in tuberculo- 
sis : (1) the simple suspicion, (2) the great probability of its 
presence, and (3) the actual existence of the disease. In the pres- 
ence of the clinically recognizable classes of tuberculosis, it is 
required that the milk from such affected animals should not be 
sold or otherwise utilized without being previously subjected to a 
required temperature for a certain length of time. 

The milk from cows affected with tuberculosis of the udder 
cannot be used for human consumption even after subjecting it to 
the required heat, nor can it be utilized for the preparation of dairy 
products. 

The requirements in Bavaria order the destruction of an ani- 
mal only when it belongs to a herd in which cattle breeding, or 
raising of cattle is industrially followed, and an appropriate volun- 
tary method of eradication "of cattle tuberculosis may then be 
carried out in the herd under veterinary supervision. 

This ought to result in a considerable improvement of the tu- 
berculosis question, and with the elimination of animals which prin- 
cipally enter into consideration as distributors of bacilli, a point 
is gained which temporarily should thoroughly satisfy even the 
milk hygienists. 

With such measures the stock owner is pleased, as the pro- 
fessional direction of rational breeding in connection with eradica- 
tion is shown to be for his advantage. This constitutes the basis 



Bacillus Pyogenes. 125 



on which the entire milk production in all its relations may be ele- 
vated, and will be elevated, since the voluntary intelligent co-opera- 
tion of the owners constitutes the fundamental principle on which 
the state bases its allowance of reimbursement. 

Without the voluntary co-operation of the producers, the 
elevation of milk hygiene is practically impossible. 

It will take years before the conditions will markedly improve, 
but the improvements will surely come, and they will not confine 
themselves alone to the tuberculosis question. 

Other Forms of Mastitis. 

The other forms of chronic mastitis, with the exception of 
tul)erculosis of the udder, are of slight importance for practical 
purposes when compared with streptococcic mastitis. 

Thus for instance the mastitis produced by the Bacillus pyog- 
enes hovis is relatively rare, and the author has had the oppor- 
tunity on only three occasions to attribute the development of 
chronic mastitis to the Bacillus pyogenes, Glage, Nielsen, Kuhl- 
mann, and Sven Wall, however, have observed the infection fre- 
quently, and even describe an epizootic extension of the infection. 
Mixed" infections of staphylococci and colon bacteria, with the 
Bacillus pyogenes, appear to be more frequent and in these cases 
a severe mastitis is produced. It results in abscess formation and 
necrosis of the affected parts, with an induration of the tissues. 
The secretion is sanio-purulent, and mostly of an offensive odor. 
Ktinnemann found the bacillus at first in suppurations of cattle, 
and Grips in suppurating processes of hogs. They are small, deli- 
cate rods of the size of the swine erysipelas bacillus, growing bet- 
ter anaerobically than aerobically, forming dew-drop like colonies 
on agar, or serum agar. Milk coagulates to a uniform clot. The 
bacillus does not take the Gram stain, but it may be stained by 
Weigert's method. 

Very little is known relative to the behavior of the Bacillus 
pyogenes hovis towards man. According to the author's observa- 
tions it appears to belong to the group of pseudo-influenza bacilli 
(Pfeiffer). Such rods were found in influenza-like pneumonias, in 
bronchitis (Pfeiffer), in suppuration of the middle ear (Kossel, 
Hartmann, Pielicke and Cantani), also in whooping cough (Afan- 
asieff, Szewetschenko, Wendt and others) . Friedberger discovered 
a similar rod in the mucus of the prepuce of a dog. Frank 
describes it in the pus of a hog. Frosch found it in the blood of 
geese, and Beck in an infectious pneumonia of rabbits. It belongs 
to a widely spread bacterial group. 

The Bacillus pyogenes is non-pathogenic for small, experimen- 
tal animals and pigeons. 

Since rods similar to those of the Bacillus pyogenes have been 
found in man it is not impossible that affections^ of man may be 
produced by milk from udders with this form of infection. 



iL^d 



Mastitis. 



It has not yet been ])()ssil)lo to (loiiioiistrate tliis l)acilliis in 
mixed milk, since there occur too many bacteria of similar mor- 
phology in stable manure, in the air, and under the epithelia of the 
teats. 

At any rate the milk nmst be considered as spoiled when it 
contains secretion from udders with pyogenic infections, and should 
be exchuled from the market, since its injurious effects upon health 
seem to have been demonstrated in the sense of tlie pure food act. 

Infections with bacteria of the coli-typhus group frequently 
occur when the cows are kept in filtliy condition, with unclean l)ed- 
ding, and also when manipulations are undertaken l)y milkers in 
order to dilate the milk ducts (penetration Mitli straws, quills, and 

Fi- 23. 






^~ 'S. 









-,v 



Cultures of Bacillus paratyt^lnis. 1 X 800. (After Kitt.) 

contaminated milking tubes). Eepresentatives of this group of 
organisms were described by Jensen and Streit, Guillebeau, Kitt, 
Freudenreich, Lucet, Sven Wall and Weichel, as the cause of high- 
ly acute forms of mastitis. The bacteria are short rods with round- 
ed ends, mostly motile; they do not take Gram's stain. Accord- 
ing to their biologic characteristics various varieties may be dis- 
tingTiished, which at times approach more closely to the colon 
group, at other times more to the serogenes group, and at times even 
to the enteritidis group, which cause meat poisoning. 

Milk hecomes coag^iilated with gas formation. The aeidifieatioii and coas^nlation 
occur earlier with some varieties than with others. The colon orroup always ferments 
galactose, yhicose, laevnlose, mannose, lactose, maltose, arabinose, rhamnose, xylose, 
mannit and sorbit, frequently also sorbose, saccharose, ratiinose and dulzit, but not 



Causes of Mastitis. 127 



erythrit and adonit. Their action is different towards saccharose, raffinose, sortose and 
diilzit, and this differentiation is utilized to separate the groups into those which do not 
attack any of the mentioned bodies, those which ferment all four, those which split up 
duhit and sorbose, and finally those splitting up saccharose and rafitinose. Of couri-e 
bacteria cannot be strictly separated by their fermentative action, since in the cultivation 
of colon strains in sugar-containing media they may acquire the faculty of fermenting a 
kind of sugar towards which they formerly were refractory (Twort, Massini). Through 
the first group the colon bacteria approach the more dangerous group of Bacillus para- 
ti/phiis B., Bacillus enteritidis of Gartner and paracolon bacteria with their related 
organisms, for instance the Bacillus raiin. Bacillus suipestifer, B. tjipM murium, etc. 
These dangerous groups may be separated by agglutination into three classes, the 
Bacillus enteritidis Gartner group, the Bacillus paratypJms B. group, and finally the 
Paracolon group. 

Weicliel succeeded in isolating from two cases of severe sep- 
tic mastitis an organism belonging to the gronp of Bacillus enteri- 
tidis, and another to the Bacillus paratyphns-B. 

Excluding the inflammatory products which may also possess 
disease-producing properties in this group of mastitis forms, it is 
necessary to exercise special care in the inflammations of the ud- 
der caused by the Coli-enteritidis-paratyplins-paracoli organisms, 
since among the representatives of this group of bacteria there are 
those which n\d.j produce severe forms of enteritis in man, with 
symptoms of poisoning, which are known in general as meat poi- 
soning. True paratyphus bacteria may also enter the milk in other 
ways than with the secretion of an infected quarter, for instance 
through bacilli-carriers who are employed for handling the milk, 
through the rinsing water, and also from other sources. It will be 
of interest to mention here the results of examinations of market 
milk for the occurrence of Bacillus paratyphus-B. 

Uhlenhuth and Hiibener twice found paratyphus in 100 sam- 
ples, while Hiibener in 40 samples of market milk noted this bacil- 
lus 4 times and in 30 other samples of market milk, observed it 
3 times. 

Klein in 39 mixed milk samples found the Bacillus enteritidis 
9 times. 

The occurrence of coli-aerogenes bacteria in milk would be 
something very ordinary, and would be considered less injurious 
for the health than the presence of varieties which are known as 
toxin producers. 

Nevertheless the coli-aerogenes infections of the udder should 
be considered with the greatest care ; although in general the enter- 
itidis and paratyphus varieties produce severe septic inflammations 
with ichorous secretions and frequently with a fatal termination, 
the severity of mastitis and the appearance of the secretion are by 
no means a certain indication of the character of the infection. 

Mixed milk to which the secretion from animals with acute af- 
fections of the udder has been added, is spoiled according to the 
pure food act, and should be considered as capable of injuring 
human health. 

The milk of healthy quarters from such infected udders is also 



1 28 Mastitis. 

suspicious of being contaminated with the infective agents, and 
therefore should be prohibited from entering the market. 

According to AVeicliel reports on paratyphns and enteritidis 
infections wliich may bo traced to milk are rare, and no publications 
can be found which absolutely trace affections iji man to a coli- 
paratyphus mastitis. 

Tlio Dairy Journal of Berlin reported in 1900 that according to "Dag. Nyheter" 
nine families in Stockholm became affected with symptoms of meat poisoninjj (fever, 
depression, faintinjj spells, nausea, vomitin<J, diarrhea, muscular cramps). The milk, to 
the consumption of which the affection was traced, originated from 14 cows, one of 
which suffered from an inflammation of the udder. In the secretion of the affected 
udiler the satne liactei'ia were found as in the feces of the affected people. 

Two female attcn<1ants of the stable from which the injurious milk was obtained also 
became affected with similar symptoms. 

The observation of Moro also ])elongs here. Moro observed in six persons after the 
consumjUion of milk from a goat suffering with a gangrenous intlamiuation of the 
udder, chills, nausea, headaches, and 11 hours later colic, vomiting and thirst. The 
milk was consumed mixed with coffee. 

Weigmann and Gruber report a case of injurious effect (vomiting), from cream 
which had been prepared from mastitis milk, and they traced the affection to a bacillus 
of the colon group (immobilis). 

Weichel fed a six-weeks old dog with the milk of a goat wdiich was artifically 
infected in the udder with a paratyphns strain from septic mastitis. The feeding was 
undertaken after the appearance of the mastitis in the goat. Three hours after the 
consumption of 200 c. c. of the secretion the dog showed marked symptoms of restlessness 
and barked frequently; lachi-ymation and later repeated vomiting appeared. He soon 
recovered but I'efused to partake again of this milk. 

Only after 60 c. c. of this fluid had been mixed with 200 c. c. of good milk would 
he touch it; he then took a small quantity but with apparent distaste. Within five minutes 
he showed pain, and manifested similar symptoms as the day before, but again recovered 
before the following day. 

In a second feeding experiment on a seven-weeks old dachshund the affection 
commenced only on the fifth day of the experiment. The animal became listless, refused 
food, whined, and in addition lachrymation, nasal discharge, and periodical chills 
appeared. This dog also recovered on the second day. 

AYeicliel also reports a case in which the wife and daughter of a 
dairyman became affected with a diarrhea after the ingestion of 
inflammatory products of a cow with coli-mastitis. The dog of the 
owner also showed similar s^^nptoms after drinking the milk. 

As milk offers very favorable conditions for the multiplication 
of bacteria of this group, the danger from milk containing coli- 
paratyphus bacteria must be considered greater than in the case 
of meat bearing the same infection. Various data exist relative to 
the resistance of these bacteria towards influences of heat. 

According to Fischer heating to 60 deor. C. for a half hour does 
not suffice to kill all paratyphns germs ; likewise some of the bac- 
teria remained active after heating the milk for 10 to 35 minutes at 
70 deg. or for five minutes at 75 deg. C. 

Although Kolle states that the typhoid, paratyphoid, and 
enteritidis bacteria are without exception destroyed when sub- 
jected to a temperature of 59 deg. C. for 10 minutes, nevertheless it 
must be remembered that the conditions in milk are markedly dif- 
ferent than in suspensions of culture, and that some of the varieties 
are capable of producing a heat-resisting toxin. According to Gart- 
ner the toxins of the meat-poisoning organisms withstand 100 and 



Mixed Infections of Udder. 129 



even 120 deg. C. These facts were confirmed by Van Ermengem, 
Drigalski, Fischer, Hoffmann, Poels, Hoist, Dhant, Riemer, and 
others. 

In practice therefore it is necessary to consider the mixed milk 
of the affected cow and all dairy milk to which such milk has been 
added as injurious to health, whenever it is proven with certainty 
that it contains secretion from acutely affected quarters. 

If it is proven with certainty that the secretion contained bac- 
teria of the paratyphoid or enteritidis group such milk may even 
destroy human health. 

Of course the danger which threatens man from such milk 
must not be overestimated. The changes in the udder and in the 
milk are pronounced and striking, and usually appear very sudden- 
ly, especially in the colon inflammations, somewhat less in para- 
typhoid and enteritidis infections. Nevertheless in the presence 
of carelessness of the milker such infections may enter the milk. 

According to Fauss the duration of the elimination of the 
bacteria from affected udders persists for 12 to 30 days, in fatal 
cases until death. The number of the eliminated bacteria and the 
duration of the elimination are proportional to the severity of the 
case, and they cease when the milk again approaches its normal 
condition. 

In other cases of acute mastitis staphylococci have been dem- 
onstrated. Guillebeau isolated the Staphylococcus mastitidis, 
Galactococcus versicolor, Galactococcus fulvus, and Galactococcus 
alhus. Experimentally it is also possible, as proven by Kitt with 
the Botryococciis ascoformans (a staphylococcus), to produce an 
acute mastitis, with a tendency to chronic development. 

The staphylococci infections of the parenchyma of the udder 
are relatively rare, but occur more frequently as mixed infections 
with the Bacillus pyogenes. While the course of the staphylomyco- 
sis of the udder is mostly acute, with a favorable progno- 
sis, yet in the presence of a mixed infection with the Bacillus pyog- 
enes it frequently results in abscess formation and sequestration 
of the udder. 

The staphylococci are small round microbes, separated into 
two or four parts by division. They take the Gram staining. They 
are easily cultivated on all media and are frequently chromogenic. 
They liquefy gelatin from the surface down, since they grow better 
aerobically than anaerobically. 

Staphylococci corresponding to their ubiquitous distribution 
are present in almost all milk during its first phases of decomposi- 
tion ; but although they possess pathogenic importance as pus-pro- 
ducers in man, from the standpoint of market milk hygiene, they 
are of no special importance under such conditions. However when 
the secretion of a cow with staphylomycosis of the udder contains 
staphylococci, the milk may be injurious to health. Karlihski, 
for instance, reports a case of pyemia in a child in which infection 



130 Mastitis. 

resulted from the milk of the mother containing- staphylococci. At 
least the cocci which Karlinski isohited from the milk, and from 
feces and blood from the child were identical. The secretion there- 
fore must be considered as spoiled food, and must be excluded from 
consumption. 

The same judgment as stated for staphylococci infections also 
applies to botryomycosis of the udder. This represents a chronic 
form of a staphylomycosis, in which the single cocci that grow 
in colonies are compressed by swelling of the cocci lying on the out- 
er borders, forming capsulated spherical colonies. The central 
cocci continue to grow, burst the capsules, and the process of the 
swelling of the bordering zone is renewed until mullierry-like fun- 
goid colonies result. A method of distingTiishing Botryococcus 
ascoformans from staphylococci has not yet been devised. The 
botryomycotic formations develop mostly in the horse which is 
probably proof of certain immunity strength of the horse (that is 
of equidia), against staphylococci infections. In other animals and 
also in cattle the disease is extremely rare. Mohler, Czokov, Immel- 
mann, and Reinhardt have observed botryomycosis in the udder 
of cows. Botryomycosis in cattle is of no practical inportance in 
the judgment of milk. 

Actinomycosis of the udder is also of slight importance from 
a practical standpoint. 

The purulent fibroplastic actinomycotic mastitis occurs in 
cattle with less frequency than the actinomycosis of other organs. 
It has been described by Rasmussen (four times), Jensen (20 
times). Maxwell (once), Bang, and Johne, and represents a chronic 
suppuration with nodular cicatrization of the udder. After the in- 
fection, nodules from a bean to a hen's Qgg in size, with softened 
centers and fibrous borders develop, or a diffuse inflammation with 
a tendency toward cicatrization and hardening of the entire udder 
results. Actinomycosis of the udder may be primary (McPhail, 
Williamson) and develop from the introduction of barley beards 
into the tissue, or possibly from pasturing on stubble fields, or again 
it may develop by metastatic formations from other lesions in the 
body. 

McPhail believes that some cases of so-called udder tuberculo- 
sis are in reality actinomycotic infections of the udder. 

Should an actinomycotic process soften in the udder and the 
abscess burst into the secreting tissue, the finding of actinomyces 
in the milk is possible. The latter appear as colonies of ray-like 
fungi (streptothrix). The branching threads form a mesh-like 
mycelimn Avitli spherical or club-shaped enlargements on the end of 
the threads. The fungous threads proliferating in the animal 
tissue are influenced by the action of the body fluids. The sheaths 
swell and club-shaped bodies result, arranged in a radiating man- 
ner, which later become adherent to each other forming rosettes in 
which the mycelium, protected from the immune bodies and leuco- 
cytes contimies to proliferate or to degenerate and calcify. 



Actinomycosis. 131 



The actinomyces are widely spread forms of the higher bac- 
teria with true branching, and stand between the lower bacteria 
and hyphomycetes. They almost invariably occur on grain, hay, 
straw, fruit, manure, soil, flour and milk. Most of the actinomyces 
are harmless provided a foreign body does not facilitate their col- 
onization in the animal body. Splinters of wood, and especially 
beards of barley are frequently the carriers of the infection. 

Transmission from man to man or from animal to man is not 
known up to the present time. The basis of an infection always 
lies in wound infection either through the above mentioned for- 
eign bodies, or by the fungi gradually becoming accustomed to exis- 
tence in necrotic tissue of the animal body (caries of teeth) . Johne 
succeeded in producing actinomycosis of the udder through the 
injection of actinomycotic cultures into the milk cistern. 

Although transmission to man through milk from actinoniy- 
cotic udders is not to be feared, prohibition of the sale of such milk 
is required since it must be considered as spoiled on account of 
the presence of pus and other associated changes. 

Contrary to actinomycosis, " actinohacillosis" first described 
by Lignieres and Spitz in Argentina, and which clinically resem- 
bles actinomycosis, is of a contagious nature. Therefore although 
actinohacillosis has not yet been described in man it should be more 
carefully judged than actinomycosis. In Germany cases of actin- 
omycosis have been reported which from the bacteriological find- 
ings, should be classed as actinohacillosis, and these cases occur 
sometimes in an enzootic form or as stable outbreaks. 

Thus Imminger in Oberpfalz and Preusse in Western Prussia, 
described an enzootic extension of actinomycosis, and Schulze 
mentioned a case in which the disease affected most of the animals 
in the stable (of 30 steers 27 were affected) . Of 87 newly purchased 
animals more than half of those placed in the stable became af- 
fected, while 12, which had been stabled on other premises and 
which received the same feed, remained healthy. 

Milk from udders affected with actinohacillosis, and mixed 
milk which contains such secretion must be considered as spoiled 
and prohibited from consumption. 

Mixed infections of the udder with these described bacteria 
and others, should be similarly judged, and likewise infections 
with malignant edema bacteria, Bacillus necrophoriis, etc. 



Chapter VII. 

EXTERNAL INFLUENCES WHICH ACT UPON MILK. 

(a) Tlieir offoet upon the body, thereby influencing milk 

secretion ; 

(b) Their elfect npon milk after its secretion. 
Although our knowledge, relative to the development of the 

individual components of milk from the substances in the blood, 
scarcely extends beyond the border of h^^pothesis, nevertheless it 
is established that milk formation is dependent to a certain extent 
upon the feeding, although' only within limits defined by the breed, 
family, individual, lactation period and age. 

Through outside conditions, those factors of production are 
especially influenced, which are themselves subject to variations, 
especially the quantity of milk and fat content, less so the proteid 
and sugar content, and only very slightly the salt content. 

The influence of feeding could be explained liy reasoning that 
the gland increases its activity at the moment in which a larger 
quantity of nutritive sulistances circulates in the blood, after the 
ingestion of large quantities of easily digested food. This sup- 
position could be even enlarged upon by considering that the activ- 
ity of the cell is stimulated by specific substances in the food in 
such a way that it assimilates to better advantage and in increased 
quantities the necessary constituents which it draws from the 
blood. 

From practical experience and scientific experiments it must 
be considered as established that the milk produced is dependent 
both in quantity and quality, upon the quantity of digestible food 
and on the presence of specific substances which stimulate milk 
formation. 

This view has boen accepted for a long time by practical dairymen, who for 
instance have observed that clover hay, in spite of its greater nutritive contents has 
not come np to the value of good meadow hay; that meadow hay cannot be replaced by 
a mixture of straw and concentrated food mixed in a way to make its nutritive value 
equal to the meadow hay; further that sweet hay proves a better milk producer than 
sour hay with equal nutritive value, etc. The value of individual pastures also shows 
wide diifferenees in the production of jnilk, although examination of the grasses of the 
pastures gives similar results. In these investigations however it was found that beyond 
certain limits the influence of nutrition was no longer usable, and that with sufficient 
feeding of wholesome and tasty food no influence could be exerted upon production 
through increased rations. 

132 



Effect of Feed on Yield. 133 



If animals are allowed to starve, the cliange in the quality of the 
milk will result only after the reserve deposits of the body have 
been utilized to their fullest extent, or completely exhausted. In the 
state of starvation the milk fat shows an approach in its composi- 
tion to that of the body fat. , 

If experiments are started with starving animals, or with 
animals which only receive small rations, the milk yield, according 
to Kellner, increases with the added increase of feed. Such cows 
after an increase of rations yielded: . -n 

With an increase of 1 . 5 kg. bean bran, the increase ot milk 
amounted to 0.92 and 0.53 kg. -, , n-. i 

With 3 kg. bean bran, the increase was 2.40 and l.Ul kg. 

With 1 kg. malt, the increase was 0.84 and 0.3 kg. 

With 2 kg. malt bran, the increase was 1 . 31 and .40 kg. 

The increase in yield however was not parallel with the in- 
crease of the ration, but the closer the quantity of milk produced 
approached the maximal production of the individual, the slighter 
became the increase in yield. In attempts to increase the produc- 
tion of the cow, the last liter of milk is the most expensive. It re- 
quires for its production the largest addition of rations. 

In general it may be said that sufficient quantities of digesti- 
ble proteins are the fundamental requirements for normal milk 
production, and that although other food substances are present m 
sufficient quantities the yield of milk diminishes rapidly when the 
protein content is decreased below the amount necessary for main- 
taining the body weight. For 1000 kg. of body weight 1.212 kg. of 
digestible proteins must be figured, together with a sufficient addi- 
tion of fat and carbohydrates. Fat and carbohydrates and non- 
protein nitrogenous substances in sufficient quantities act as econo- 
mizers of proteins. For continuous milk production an excess of 
about 0.40 to 0.55 to 0.65 kg. of digestible proteins is required 
for 10 kg. of milk (Schmeck and Kellner). 

Experiments of Morgen and Fingerling proved that while 
feeding tasteless non-stimulating food consisting of straw, cut 
straw, starch and oil, the yield of milk may be increased by the ad- 
dition of substances which by themselves cannot be utilized in the 
production of milk, and therefore they are considered stimulating 
substances which principally stimulate the gland to activity. 

Increased Increaped 

Addition yield yield 

in milk m fat 

Malt... g™- ^^^• 

Buckhornseed 10 gm. 0.8 gm. 

Hay distillate and fennel 2.03 gm. 7.9 gm. 

153 gm. 5.6 gm. 

312 g-m. 9.8 g-m. 

109 gm. 6.7 gm. 

The percentage of fat increased 0.25 to 0.32^0. 



;[34 Effect of External Influences. 

In order to produce an increase of milk it was sufficient to 
introduce into the food small amounts of fennel, or to sprinkle it 
with distillate of hay. If in the experhnents good meadow hay was 
fed in sufficient quantities with other food-stuffs, the addition of 
the stimulating substances was without effect. These observations 
are of special importance in view of the swindles carried on with 
milk powders, by which money is still extorted from the farmers. 
Through the addition of salt to tasteless food an increased yield 
in milk and fat was obtained amounting to from 20.6 to 21.9%. 

Hansen reports on the influence of concentrated foods on 
the milk yield, which he investigated extensively for seven years. 
This author divides the concentrated food into four groups : 

1. Foods which increase the milk yield and diminish the 
percentage of fat, as for instance farina, corn, oats, and possibly 
also soja beans. 

2. Those which do not influence the quantity of milk but 
increase the fat content, as for instance palm-seed oil and cocoanut 
oil cakes (the specific action of cotton-seed meal is less pronounced) 
peanut meal, corn-slop and bread flour. 

3. Those which do not change the yield of milk but reduce 
the fat content, as for instance, poppy seeds, flour of rice and other 
concentrated food, beneficial for fattening, as for instance cake of 
sesame (Eamm). 

4. Those which have no specific action, as for instance wheat 
bran, and malt sprouts. Such food substances are especially de- 
sirable for the use of fattening dairy cattle. 

From the experiments of Hansen it appears as a matter of 
fact, that certain food substances possess a specific action. In 
this regard the composition of the food is of course of importance, 
since the action of a certain food may be checked by feeding coun- 
teracting substances. It has long been known from practical ex- 
perience that the quality of milk may be greatly influenced through 
the method of feeding, and not only as far as the constituents of 
the milk are concerned but also its odor, taste, etc. To what extent 
food bacteria play a part in this, will be discussed in the chapter 
devoted to that subject. 

Summer butter, moxintain butter, and stable butter, are rieber in fatty acids with 
low molecular weight, than fall butter or butter from cows which have been kept on 
low land pastures, or pasture butter in general prepared in the same manner. Feed rich 
in carbohydrates produces a soft milk fat. If abnormal constituents of fats are 
artificially added in experimental feeding, or if fats are fed which are otherwise not 
found in the body, such constituents are again found in the milk, for instance sesame 
oil (Engel), linseed oil, hemp seed oil (Gogitidse), iodin and iodipin (Caspari and 
Winternitz), Sudan III, a specific fat coloring matter (Gogitidse). 

According to Schrodt and Hansen pasture milk on account of 
its greater contents of casein, contains more phosphoric acid than 
staijle milk, which on the other hand is richer in chlorin. Accord- 
ing to Sanson, Hesse and Schaffer the feeding of phosphate also 
increases the content of phosphoric acid ; this however according 



Feed Recommended. 135 



to Neumann is not immediate but appears only after weeks and 
then in insignificant proportions. Jensen succeeded in finding only 
an insignificant influence on the milk from the feeding of considera- 
ble amounts of lactates of iron, calcium sulphate, disodium phos- 
phate, dicalcium phosphate, dimagnesium phosphate, potassium 
chloride, chloride of sodium, and nitrate of potassium. Nitrates 
appeared in the milk only after 75 gm. of saltpetre had been fed. 
The administration of from 30 to 40 gm. of saltpetre failed to result 
in the presence of nitrates in the milk. The salt content of milk 
therefore changes only insignificantly provided normal conditions 
are present. According to Henseval and Mulhe, the health of the 
animals plays a part when salts pass into the milk. If these authors 
fed from 5 to 25 gm. of saltpetre to 20 healthy and 8 diseased 
animals, the milk of the sick animals always contained nitrates, 
whereas the milk of the healthy animals did so only exceptionally. 
Definite quantities of sulphuric acid are supposed to occur m milk 
after the administration of Glauber salts. 

Of the various foods, meadow grass, green clover, rowen, 
green alfalfa, and peas in which a large amount of young grain has 
been sown are recommended, for instance, vetch with oats, barley 
or rye, plants of the white mustard, rape, sainfoin. Kohlrabi tur- 
nips, etc., with which oats, barley or rye have been grown. Fod- 
der or straw should be mixed with the green feed. In the winter 
instead of green feed, mangels, chopped roots, ensilage, gram, 
potato slop and corn slop should be fed. 

Relative to the injurious effects of the various bacteria found 
in feeds and pastures, see the chapter on milk abnormalities. Good 
hay and good fodder may be recommended as dry feed. As con- 
centrated food the substances mentioned by Hansen as indifferent, 
or those food substances of the first and second group which are 
recognized as milk and fat producers, will be found satisfactory. 
Eough fibrous foods cause a loss of energy, and are not well 
utilized on account of the increased work of mastication and be- 
cause the intestines are too greatly burdened by this feed. Individ- 
ual feeding according to the milk yield appears advisable, and 
the best milkers may be allowed additional rations corresponding 
to their heavy production. In this regard of course the yield and 
quality of the milk should be established by sample milkings and 
examination of the secretion. In cow-fattening dairies the fatten- 
ing of the animals should commence only in the last three months 
since fattening foods and fattening of the animals diminish the 
yield of the milk. 

Pure drinking water has a great influence on milk produc- 
tion, and the animals should be enabled to partake of it freely ac- 
cording to their needs. Heyken mentions a case in which each cow 
yielded one-half liter of milk per day more, when instead of hard 
marshy spring water containing iron, good well water was sub- 



13G ' Effect of External Influences. 



stituted. Backliaiis observed an increase of milk and fat con- 
tent after the introduction of an automatic water supply. 

Milk of poor quality is known to have resulted from the use 
of poor drinkino- water. Stagnant waters give tlic milk a repulsive 
taste. 

Taken as a whole all foods and all food mixtures which are par- 
taken of and digested by the animals without disturbance in their 
general condition are adapted to the feeding- of milk animals. Food 
which in continuous feeding- causes diarrhea or other intestinal 
disturbances should be avoided. Intestinal disturbances which 
quickly sul)side and which sometimes develop as a result of sudden 
change of food are of no consequence in the judgiuent of the food. 
They may cause considerable fluctuation in the yield of milk and 
fat content, which however subsides in a few days. From the 
above statement it will be seen that under certain conditions, espe- 
cially when a heavy production of cream is necessary, the effects 
of ^ a change of food must be considered. If, when considering 
evidence of adulteration, methods of examination are used which 
take note of the approximately constant factors in milk, that is, 
such as pertain to the protein-free milk serum, the influence of a 
feeding method, or a sudden change of feed should be taken into 
consideration in regard to its effect upon the milk of each indi- 
vidual animal. 

Spoiled food injures the taste and odor of the milk and 
butter, and its effects may last for a long period after the time of 
feeding such food. The feeding of large quantities of beet or tur- 
nip tops should be guarded against, likewise over feeding with 
fresh or sour chopped roots, potato slops, residues from starch 
factories, brewer's grains, rape seed cake, flaxseed meal and poor 
straw. 

The taste is improved by feeding on pasturage, red clover, 
meadow grass, carrots, oats and rice flour. 

Firm tallowy butter is derived from grass of acid soil, from 
grass from fall pastures, late hay made from sour grasses, leaves 
of sugar-beets, or red beets, chopped roots, potatoes, peas, palm 
seeds, cocoanut and flaxseed cake, and cotton-seed meal. 

Soft butter results from the feeding of oat hulls, corn bran, 
wheat bran, rice flour, rape-seed cake and sunflower-seed cake. 

Clover pastures are not suitable for the production of milk for 
cheese making since the cheese becomes permeated with small holes, 
and has a sharp repulsive odor. This condition is probably brought 
about by bacteria Avhich vegetate on the clover plants of the 
pasture. 

Changes from one feed to another should not be made too sud- 
denly if it is desired to prevent an effect on the milk production. 
NcAvly introduced food substances should not be fed in large 
quantities at first. In changing from dry food to pastures a dimin- 
ished milk yield first results, then a period of normal yield and 



Plants Affeetins Milk. 137 



finally an increase in the quantity, together with an improvement in 
quality. Pastures or green cultivated forage containing many 
buttercups should be avoided, since these plants are supposed to 
produce red and bitter milk, especially before blooming. Meadows 
or pastures in which Euphorbia plants are growing exert a bad 
influence ; they may produce enteritis with a fetid diarrhea, also 
paralysis of the bladder and hematuria, and may even cause abor- 
tion. The milk turns thin and bluish. 

Bluish milk may also result after feeding upon plants of the 
Polygonum species, the ox tongue (Anchusa offic), the cat's tail 
(Butomus umbellatus), the euphorbia (Mercurialis), the marsh 
marigold (Ehinanthus major), the forget-me-not (Myosotis), and 
after feeding upon poppy-cake and green alfalfa. 

Red milk is produced by feeding blood root (Galium verum), 
madder (Eubia tinctorum), species of Karex, Skirpus, Equisetum, 
Eanunculus, Euphorbia and after the ingestion of young sprouts 
of both deciduous and coniferous trees. 

Yellow milk results from the elimination of plant coloring 
matter after the feeding of carrots, rhubarb, yellow and red man- 
gels, and crocus. 

A garlicky taste may also result from feeding large quantities 
of poor straw, and according to Werenskiold after feeding of flax 
seed meal which contains large quantities of weed-seeds, penny- 
royal (Thlaspi arvense). The taste of the milk may also be 
changed by the ethereal oils of the following plants : 

Garlic (Alium ursinum), mint (Teukrium), hyssop (Gratiola 
offic), true camomile (Matric. chamomilla), and by rape, rape- 
cake, oil cake, turnip tops, lupins and orchids. 

Milk may become fishy from feeding fish meal and through 
pasturing on marshy fields which have been inundated. 

Milk turns bitter from feeding kale, rutabagas, turnip tops, 
lupins, pea-straw, lupin straw, and sorrel. 

A bitter substance from chicory passes into the milk; the 
milk may coagulate more readily after the ingestion of thistles or 
sorrel. The ingestion of euphorbia, hellebore, rushes, and hemlock 
twigs should be prevented on account of the poisonous qualities of 
these plants. The secretion of the active poisons of these plants 
has, however, not been proved. Hop leaves, especially those 
sprayed with copper sulphate, cause a diminution of milk secre- 
tion, or even a cessation of the flow. 

Concerning the elimination of medicinal agents with the milk, 
or the influence of medicinal agents on milk production the follow- 
ing may be stated : The passage of iodine into the milk after feed- 
ing potassium iodide has been proved by Peligot and Stumpf; if 
however the iodine is fed in alkaline compounds, or combined with 
proteins and starches, even when fed in large quantities, it does not 
pass into the milk. In the latter case only the plasma of the milk 



138 Effect of External Inllucnees. 

contains the halogen in the form of a salt, whereas in feeding 
iodized fats the milk fat contains iodine. 

According to Eosenhanpt and Bncura the same applies to 
bromine. 

According to Stnmpf, Bamn and Seeliger, in feeding com- 
ponnds of lead small qnantities (0.02%) of this snbstance pass into 
the milk. The ingestion of such milk was fonnd harmless for ani- 
mals. The lead was eliminated for a longer period than the time 
during which it was fed. Milk which contains salts of lead could 
produce severe injurious effects if taken for a long time (chronic 
lead poisoning). 

Feeding of salts of copper results only in the appearance of 
traces of copper in the milk. 

The feeding of iron preparations does not to any noteworthy 
extent influence the contents of the milk. 

Mercury may pass into the milk (Bucura) ; likcAvise arsenic 
when administered per os or injected in any form subcutaneously 
(Bucura, Ittalie and Jesionek). 

Substances like aloes, senna leaves, rhubarb and croton may 
influence the milk in color and taste, and will be partially eliminated 
with the milk. 

According to Eost and Wiley boracic acid may pass into 
human milk; likewise after the ingestion of Glauber salts the 
SO3 content of the milk is supposed to be increased (Hess and 
Schaffer). 

According to Baum tartar emetic is not found in the milk of 
cows treated with this drug, whereas Harms claims it is eliminated 
with the milk. 

The feeding of large quantities of alcohol effects a diminution 
of the specific gravity and an increase of the fat content of the 
milk. The quantity of the milk appears somewhat increased (in 
goats). Elimination of alcohol with the milk does not occur. Wel- 
ler and Teichert proved that alcohol would pass into the milk of 
cows after feeding them vitli large quantities of incompletely ex- 
tracted distillery slops. 

Although Horder and Herdegen claim the secretion of salicylic 
acid with the milk, Eichter, Pauli and Stumpf disclaim its 
elimination in large amounts. Pauli and Stumpf succeeded in de- 
tecting small quantities of salicylic acid in the milk of nursing 
mothers treated with this substance, and also in the urine of their 
babies, as well as in the milk of experimental goats. In this regard 
individual peculiarities must also be considered since in one nurs- 
ing mother the presence of salicylic acid was demonstrated, where- 
as the examination was negative in another case. 

According to Pinzoni the same applies to antipyrin. Salol 
does not appear in the milk after its administration. 

Chloroform and ether are found in considerable quantities in 
the milk after anesthesia (Nicloux). 



Drugs affecting Milk. 139 



Landsberg failed to detect morphine in the blood, nrine or in 
the organs, either after subcutaneous or intravenous injections, 
and Stumpf and Pinzoni do not believe that after therapeutical 
administration of morphine it will pass into the milk in demon- 
strable quantities. This was found by Ittalie to be the case with 
opium. 

Oil of turpentine is not eliminated with the milk (Ittalie), 
and the same is true of santonin (Coronedi). 

Stumpf undertook experiments with pilocarpin without how- 
ever being able to find the pilocarpin in the milk, although his 
methods were unsatisfactory. 

Atropin and fluorescin administered subcutaneously, accord- 
ing to Fugin and Bonanni, and Ittalie, may be demonstrated in 
the milk. 

It should also be mentioned here that according to Ostertag meat of poisoned 
animals may be eaten without harm to the health. He established the fact that meat 
from animals which have received medicinal agents for therapeutic purposes may be 
consumed without any possibility of danger. The harmlessness of the meat of poisoned 
animals has been established by Frohner and Knudsen for strychnia, eserin, pilocarpin 
and veratrin; by Harms for nux vomica and tartar emetic; by Feser for strychnine and 
eserin; by Spallanzini and Zappa and Sonnenschein for arsenic; by Gautier for cotton- 
seed cake ; by Feser for apomorphine ; by Peschel for colchieum ; by Warnke for morphine ; 
and Albrecht for litharge. 

Of course milk may contain certain quantities of poison since the udder has a 
special function as an excretory organ. The question of elimination of medicinal remedies, 
however, is not of practical importance since the medicinal doses are relatively small 
and their elimination occurs only in traces. 

In this entire question milk inspection is powerless. Through 
educational advice by the consulting veterinarian the producers 
may be reminded of their duty corresponding to the prohibitive 
measures, not to include with milk for the market that produced 
by animals which are under treatment with certain drugs. From 
a hygienic standpoint only those remedies deserve mention which 
are eliminated for a long period after their administration, as for 
instance lead and medicines whose prolonged ingestion may pro- 
duce disturbances of health even in the smallest doses. 

Considering the fact that in normal feeding with good feeds 
of any kind the individual influence is paramount in milk produc- 
tion, it becomes evident that in establishing regulations for pro- 
curing children's milk more stress should be laid on the health of 
the animals, on good attendance and care by healthy milkers, and 
on thorough cleanliness of the stable, and cleanliness in procuring 
and handling the milk, than on rigorous regulations for feeding 
which cannot be satisfactorily carried out by the owner on economic 
grounds, since he must utilize the by-products or refuse of any 
industry of his vicinity. 

There is no reason why pasture milk, or milk obtained after 
feeding green food should be excluded from the market as certified 
or children's milk, especially if from a dietetical standpoint the 
advantages of green feeds for cattle are considered, and the f avora- 



240 Effect of External Inlliiences. 



ble influence whicli the pasturing- exerts on milk production and 
metal )olism be regarded. 

Spoiled feed should be prohibited, and also foods which are 
readily subject to decomposition (fresh residues of breweries, 
sugar refineries, etc.). Food which is obtained through fermenta- 
tion processes (hay, grass, clover, mangels, potatoes, green corn, 
stored in pits in the ground) should if possible be limited, since 
substances of odor and taste are eliminated with the milk and 
especially food bacteria which diminish the keeping qualities of 
the milk. Although they might not have a direct harmful influence 
in the Imman organism nevertheless they may spoil the taste of the 
milk. 

The beneficial influence of i^asturage cannot alone be attributed 
to the advantage of change of feeding, but is also the result of the 
stimulating action of the light and air on metabolism, and of the 
mild form of exercise. Therefore in the absence of pastures it 
would be advisable to provide exercising paddocks for the animals. 
According to Munk moderate exercise increases the yield of milk 
and its proportion of solid substances. 

Excessive exercise of cows should be avoided. 

Although moderate exercise on rich pastures in connection 
with other factors Avhich increase metabolism, produces more 
abundant and richer milk, increased exercise reduces the quantity 
of milk but increases its fat contents. In over-exertion however 
the quantity and quality of the milk are reduced, and the milk and 
butter both develop an irritating taste (Dolgich). 

Exhausting transportation changes the milk production con- 
siderably, especially when during that period the cows are milked 
irregularly, or for advantage in selling the cows the ndders are 
allowed to become engorged with milk. Stasis mastitis results, 
which may be cured only by repeated and thorough milkings. 

Excitement of any kind, such as fright, taking away the calf, 
change of surroundings (new purchaser), and change of feed, may 
for a longer or shorter period cause a diminution of the quantity 
of milk and a change of its quality. 

Backhaus observed an increase of over 7% in quantity of 
milk production and 8% of the fat content after the cows had been 
curried; in other cases it amounted to 4 and 21/0%, respectively. 

In pasturing cows, sheds should be provided for shelter from 
the strong rays of the sun and rain ; otherwise according to 
Schwenk the yield liecomes diminished. Kirsten observed a dimin- 
ution of the production of milk after prolonged rain. According to 
Ingersoll and Duncanson, marked changes in the weather may 
even be of significance during the season Avhen the animals are 
stabled. 

A rise or a fall in the temperature may cause a reduc- 
tion in the fat content. In the morning following rainy nights the 
milk may become richer. The influence of weather and pasture on 



Method of Stabling. 141 



milk production has been observed by various German investiga- 
tors, but the results differed considerably. Some observed a dimin- 
ution of the fat content, others an increase, while some noted a 
diminution of the milk yield, and a number of others detected 
no reaction whatsoever. Following the passage of a heavy thunder 
shower a diminution of the milk yield and an increase of the fat 
content were observed which corresponded to the increased activity 
of the animal in the equalization of the body heat. 

If herds which are pastured at night are compared with those 
which are stabled at night, no favorable influence of the stabling 
at night is observed, neither regarding the quantity of milk nor its 
fat content. In animals kept uninterruptedly out of doors the fat 
content increased more rapidly than in those kept in stables. In the 
former the live weight increased more rapidly than in the latter ; 
in other experiments, however, the results remained the same. 
Wychgram in his experiments in East Friesland found the milk 
yield in stabled animals increased, but the fat content diminished 
as compared to milk from cows at pasture. 

The cows which furnish the milk supply of cities as a rule are 
kept in large stables. The stabling of course should be such that 
the health of the animals does not suffer, and means should be 
provided for a pure milk production. 

It is not so difficult to comply with these two requirements as 
some farmers believe. They may be attained without great ad- 
ditional cost, since the increase of expense for proper stabling is 
amply covered by the increased income from the animals. 

In equipping so-called model stables, an extraordinary amount 
is usually expended for luxury in the equipment and furnishings, 
so that the practical farmer on visiting such stables is frequently 
disheartened, instead of being encouraged to change his more 
primitive place of milk production to comply with these models, 
since a simple calculation of the expense of such buildings for keep- 
ing cows shows him that a change of his stable conditions to equal 
those of the models is impossible. 

A really valuable modern stable however may be built at the 
present time without considerable additional cost, and may be 
equipped so that the additional expense of milk production due to 
the wearing out of the building is not greater than the cost of 
repairing an unsanitary stable. 

For the erection of a new stable a dry building site should be 
chosen if possible, or at least the penetration of dampness from the 
ground should be prevented through separation and isolation of 
the ground and walls. Only under such conditions can the require- 
ment of clean walls be attained. 

The floor of the stable must be water tight and without cracks 
and holes, and should permit of ready cleansing and disinfection. 
It is to be regretted that such water tight floors are frequently too 
cold for milk cows, and the action of the cold must be diminished 



142 Effect of External Influences, 

by the provision of wooden planks. The floor surface must be 
rough enough to afford the animals a solid footing. 

The walls of the stable should be provided to a height of 6 feet 
with an unpenetrable, washable covering, which however should 
not be dark as was customary in the past, in order to hide the ac- 
cumulated dirt, but should be light in order that dirt may be readily 
seen and removed. 

The stable ceiling should be separated from the feed loft 
situated above it, by an air space, and should be whitewashed, the 
same as the walls. In order that it should be impervious to the sta- 
ble odors, the ceiling on the inside of the stable should be covered 
with minerally treated pasteboard. The air space between the 
ceiling and feed loft should communicate with the outside air. 

Angles and corners should be rounded off, in order to prevent 
the accumulation of dust. 

In large herds the erection of several small separated stables 
should be given preference to a large single stable for all animals. 
Each of the stables should be made for 16 to 20 animals. The 
advantages of the smaller buildings are manifested in better pos- 
sibilities of ventilation, the easier removal of manure, cheaper con- 
struction of the roofs, less excitement for the animals, and better 
possibility of caring for and feeding the individuals. Against these 
advantages the absence of close supervision, which is afforded by 
the large stable, is not material (Schuppli). 

The animals should be placed in rows in such a way that the 
light may strike them from the side or from the rear. 

In order to provide a great amount of light, high, broad win- 
dows and transparent instead of only translucent window glass 
should be installed, the total lighting surface of which should 
amount to at least one-twentieth of the floor space of the stable 
(according to Schlossmann the comparison should not be much less 
than one-fifth). 

Placing the animals face to face should be avoided on account 
of the danger of infection with tuberculosis, or this danger should 
at least be diminished by broadening the passages. 

The windows should commence from 5 to 6 feet from the floor. 
Artificial illumination should be provided for; transoms assist in 
the airing of the stable by allowing ingress of natural atmosphere. 

The ventilation should be calculated so that the air of the sta- 
ble should not contain more than 3:1000 (Marker), or 1:1000 
(Schlossmann) carbonic acid. According to Schlossmann a cow 
weighing 1,100 lbs. produces 12.71 cubic feet of carbonic acid, 
which would have to be diluted by 1,000 times its quantity of in- 
troduced air in order to contain only 1 :1000 of the required quan- 
tity in the air. This introduction of air is made possible by three 
changes of air per hour, without permitting a disturbing draught. 
Therefore, according to Schlossmann, the air space in a stable for 
cows weighing 1,100 lbs. must be 12,710 :72==176.5 cubic feet. Gen- 



Stable Construction. 143 



erally however, on account of economic grounds a much smaller 
air space has to answer the purpose. Schuppli even believes that 
a reduction of air space below the ordinary 70 to 88 cubic feet of 
air per animal would be permissible when the ventilation system 
is working properly, and is satisfied with 42 cubic feet per animal 
when the ventilation provides for sufficient renewal of air. 

The supply of air is provided by wide shafts which take the 
air from the outside at a height of three feet, lead it up through 
the wall and expel it from the stable ceiling into the stable. The 
foul air escapes through an opening close to the stable floor of one 
or more discharge shafts, which are carried to the highest point of 
the stable ceiling, or sideways from the median line upwards and 
outwards. The total capacity of the discharge shafts should be 
somewhat smaller than the capacitj^ of the supply shafts. 

In intensive ventilation, especially when the air space provided 
for each cow is considerable, heating of the stable might become 
necessary, a provision which of course could not be considered for 
the ordinary, medium-sized or even larger establishments. 

Well-installed transom ventilators, if sufficient attention is 
given to their operation, would supply the desired change of air 
even without heating, and at the same time maintain the desired 
temperature of 16° to 18° C. If heating is provided the air sup- 
ply shafts should open over the heaters. 

In providing stalls, from the standpoint of cleanliness only 
the so-called Holland type of stable floor should be recommended 
for dairy stables. The principle on which these are built consists 
of rather short standing space with broad, deep drainage trough 
in the rear. The urine and manure falls into this trough, and 
soiling of the animal is thereby prevented while the contamination 
of the bedding is minimal. 

Among objections to the Holland type of stables, it is sometimes claimed that the 
animals cannot move sufficiently and that such stabling constitutes a cruelty to the 
animals, etc. The best proofs against these objections without doubt, are the facts that 
in countries which are in the highest state of agricultural development this method of 
stabling has been practiced for a long time, and the animals soon get used to this method 
of stabling without suffering in their general condition or being affected in their milk 
production. 

In the Holland method the tails of the animals are tied with a 
cord in such a way that while the animal stands its tail hangs in 
a natural position, but when lying down the tail is kept elevated 
so that it cannot be submerged in the contents of the drain. 

The cords are tied to a rod which runs near the ceiling, parallel 
with the row of cows, or the cords, with weights attached, are 
allowed to hang over this rod. 

The shortness of the stalls of course requires a low feeding 
trough, over which the animals may extend their heads while lying 
down. In order that the animals may not annoy each othei*, the 
individuals are separated by means of partitions, which extend 



244 Kft'ect of External Innuences. 



upwards to the height of the head or the shoulder and at the same 
time have fastenings which are nsed for tying the cows. 

To prevent the cows from backing into the drain, a monklinp: 
of one-half inch is provided along the upper border of the drain 
trough. This moulding holds the slipping foot and makes possible 
the placing on the floor of wooden slats when pregnant animals are 
about to calve. The fundaiiiental principle against tlie possilnlity 
of slipping is the above-mentioned provision of a sufficiently rough 
stable floor. 

The width of the stalls should be about oY- feet, the length 514 
to 5:'4 feet. 

The most satisfactory feeding troughs are those which cor- 
respond to the conditions of natural feeding in the pasture, and 
they should be so constructed that they w^ill serve for animals of 
all ages with the possibility of providing partitions in order to 
separate the individual rations. For watering the animals it is 
advisable to provide each stall with automatic water supply. 

The accumulated litter in the drain trough should be mechan- 
ically removed as often as possible into liquid manure pits which 
terminate in a tunnel with collecting canals, or the litter may be 
thrown into a chute through a shaft leading to a water-tight liquid 
manure pit the size of which should be so arranged that 88 to 106 
cubic feet of manure space are allowed for each animal. 

Over the liquid manure pit on wooden lattice frames, or along- 
side of it, should be placed the manure pile, with 30 square feet of 
surface for each grown animal. On account of the desired decom- 
position of the material the first-mentioned arrangement of the 
manure over the liquid manure pit is most desirable. There should 
be a separation between the stable and the manure pile of at least 
20 feet and the latter should be placed on the side opposite to the 
principal direction of the wind in that locality. The outlets of 
the manure drains should be closed from the stable by trap or slid- 
ing doors. 

Good straw should l)e selected for the bedding of animals. 
The question of straw which is very important in localities where 
but little is grown is favorably solved by the Holland method of 
stabling, since by this method a great deal of straw is saved by 
the short stalls with but slight soiling of the animals. Forest and 
shade leaves are not recommended, since it is claimed that milk 
troubles result from their use. Turf straw, shavings and saw- 
dust should l)e avoided if possible on account of the formation of 
dust, but should not be excluded if good straw bedding cannot be 
obtained. The use of bed straw should be prohibited in milk 
stables. The feeding of the cattle must be performed after milking, 
on account of raising the dust. The removal of the manure and 
the cleaning of the animals should take place at least one hour be- 
fore the milking. 

Complaint is frequently made to hygienists that the require- 



Complete Milking. 145 



ments wliicli are made by them relative to stable hygiene must in- 
crease the cost of keeping the animals, and thereby increase the 
cost of the milk. This view is only justified to a slight extent. 
Stable hygiene if satisfactorily adjusted will result in a considera- 
ble increase in the yield of the dairy animals. 

The economic losses which are induced by udder affections, 
which spread with especial rapidity in filthy stables and from 
unclean milking, have been discussed in a special chapter. Atten- 
tion should only be directed here to the increased production fol- 
lowing proper attention to cleanliness of the animals, and to the 
findings of Bloymeyer and others, according to which cows in well 
ventilated stables, all other things being equal, yielded from 450 
to 480 liters more milk per head each year than cows kept in unven- 
tilated stables. 

The favorable influence of exercise and light work has also 
been discussed above. If possible the animals should be given an 
opportunity to run out of doors in a paddock for at least one to two 
hours daily, even in the winter months. 

Of all outside influences, regular and complete milking con- 
stitutes the most prominent stimulant for inducing the activity of 
the udder. It is known that cows which are milked three or four 
times in each twenty-four hours give more milk than those which 
are milked only twice (Backhaus). The increased yield from milk- 
ing three times amounts to from 10 to 15% more than the pro- 
duction obtained from two milkings ; in four milkings the increase 
amounts to from 6 to 8% as compared with three milkings. 

The quantity and composition of the milk at each milking de- 
pend somewhat upon the time which has elapsed since the last milk- 
ing. According to general experience the morning milk is of 
greater quantity with a smaller amount of fat, in comparison with 
quantity and fat content of the evening milk. During the night 
absolute rest prevails, whereas during the day the influence of light 
and motion causes an increase of metabolism which is also mani- 
fested in the variations of the body temperature shown by the 
animal in the morning and evening. 

The differences in milk, which are obvious in irregular or 
so-called broken milkings, may be explained in a different way ; that 
is while the milk at the beginning of the milking contains 0.5 to 
1.5% fat, in the middle of the milking it shows 2 to 3 to 4%, and 
again rises towards the end, during the last strokes of milking to 
8 and 10% (Melander, Kaull, Gotta, de Vrieze). The fat-free solid 
substances are subject to slight changes (according to Boussin- 
gault the fluctuation amounts to from 0.2 to 0.28%). The condi- 
tions in the milk when the calf sucks are similar. 

A truly plausible explanation can hardly be given to the supposition of a separation 
of cream in the udder (Zschokke) ; likewise it hardly seems reasonable to suppose that 
the thin plasma particles flow towards the cistern, while the fat globules as a result of 
greater fusion and friction are retained, and are only pressed towards the larger milk 
duets and the cistern by the newly formed milk which is secreted during the act of 
10 



14:6 Effect of External Influences. 



milking. The principal cause lies probably in the fact that the separation of the fat 
represents a greater expenditure of euergy than the secretion of the plasma. If the cell 
is exhausted by previous milking it then secretes milk during the period of rest which 
is especially rich in jilasma and poor in fat. Through this period the alveoli and milk 
ducts are dilated, and the gland cell becomes Hat and is at rest. In this position of 
rest it recovers and is ready for renewed action when, through renewed milking 
operations, the lluid is withdrawn and stimulation of the secretion is applied through 
the teat. 

If the milk is removed without this stinmlation of secretion, with the aid of a 
milking tube, only milk poor in fat Hows from the cistern and the larger milk ducts, and 
the How ceases as soon as pressure is no longer exerted on the secretion. 

If, however, through milking (or other stimulation) new secretion takes place, the 
rested gland cell engorges with nutritive material, and converts it into fat, which is 
separated during the milking in increased quantities until the secretion of plasma and 
the separation of fat cease, Avhich marks the height of these two processes in the 
secretion of milk. Through an increased stimulation l)y additional milkings the cell 
may be further stimulatecl to a special production, which consists in an increased fat 
formation (Ilegelund). Henkel succeeded by this procedure, in increasing the quantity 
of milk by 2.4%, and the fat content by 6.2%. 

As already mentioned Hegehind's method requires additional 
work, Avliicli maj^ possibly lead to the hiring of additional help 
and must be considered (Kirchner), when estimating- profit and 
expense. The principal factor in the various methods of milking 
lies in the thorough milking out of the udder, which will retain 
its maximum of production only by such practice. Henkel suc- 
ceeded in demonstrating the extent to which the milk production de- 
pends on the thoroughness of the milker. The production of a cow 
when luilked by a thorough milker amounted to 8.1 kg. (17.8 lbs.) 
of milk, with 4.2% of fat; bv a less satisfactory employee to onlv 
5.6 kg. (12. 31bs) with 2.7% of fat. ^ 

At the same time it is immaterial what method of milking is 
pursued, that is, whether the teats are milked crosswise, or those 
on one side, or those of opposite quarters, simultaneously. Milk- 
ing of a single teat at a time, which of course is not customary, 
yields less milk, and the last milked quarter is the poorest in fat 
(Lepoutre and Babcock). The influence of special methods of milk- 
ing has been more fully discussed in the chapter on the procuring 
of milk. According to Klinkmiiller the milk yield of the right half 
of the udder is 3.97 kg. (8.7 lbs.), the left 3.65 kg. (8.03 lbs.), with 
fat contents of 3.65 and 3.31% respectively. The cause of this 
increased production of the right half of the udder is, according 
to Klinkmiiller, the result of the practice of milking the right half 
first, and therefore it is advisable to practice alternation in milking, 
from right and left. 

If milking stools are used care should be taken that the 
milkers do not take hold of the seat with their hands. The most 
recommendable stools have only a single foot, and are secured 
around the body by a strap. Switching of the animal's tail must 
be prevented during milking by tying it up, or by other effective 
contrivances. 

Conditions which prevail in the handling of milk after it has 
been procured are of special importance in providing milk of the 
best quality. The changes which milk undergoes have been dis- 



Milk Pails. 147 



cussed sufficiently for the purpose of milk hygiene in special chap- 
ters. Those points principally should be emphasized which are to 
be followed during the drawing and preparation of the milk,^ in 
order to check or prevent undesirable and early decomposition 
of the product. 

This relates primarily to cleanliness. The requirements of 
milk hygiene go hand in hand in this respect with the purely 
economic requirements of the dairy industry. 

If it is considered how much milk spoils prematurely on ac- 
count of improper care and the amount of loss which is sustained 
when the creameries have to discard hundreds of pounds of cheese 
on account of improper handling of milk, then the economic value 
of cleanliness in the stable becomes obvious. The Holland method 
of stabling, cleaning of the cows and especially the udders are 
quite simple but important factors in such cleanliness. 

In keeping- the udder clean special attention should be given 
towards preventing its contact with filth. 

Dry cleaning with suitable straw, or rough towel is prefera- 
ble to moist washing which often consists in spreading the softened 
dirt over the entire udder. If the dry method of cleaning the ud- 
der is used such milking pails should be provided which will pre- 
vent the milk from becoming contaminated by the dust originating 
from the cleaned udder. 

If the udders are washed it should be done with lukewarm 
water without soap. Subsequently the udders should be rubbed dry 
and slightly lubricated with paraflin salve. Even with these simple 
operations milk may be obtained containing only very small num- 
bers of bacteria, and would suffice for all practical purposes. Cov- 
ering the animals with linen sheets, disinfection of the udder in 
water-tight bags, and washing of the entire animal represent some- 
what exaggerated procedures, and besides they require additional 
expense, which can be afforded only through a special increase of 
the price of milk. 

The milk pails should be so constructed that they will pre- 
vent dust and dirt from falling into the milk. This is accomplished 
by using covered pails, which possess a special receiving tube sup- 
plied with a funnel for taking in the milk. Between the receiving 
tube and the funnel an arrangement for filtering through cotton 
may be placed. The so-called Algauer milk pails are provided 
with such arrangements ; likewise the Konigsf order milk pails and 
the" sanitary pails of Gurler and North. The funnel should be 
rinsed and provided with a fresh piece of cotton after the milking 
of each cow. 

After milking is finished the milk should be immediately taken 
from the stable. This is frequently accomplished by pouring it 
into a funnel arrangement fastened to the wall through which 
the milk passes into a suitable tin lined tube to the milk room. 
This tube should be removable in order that it may be properly 



;}48 Effect of External Influences. 

cleaned. In the milk room the milk is further treated by another 
straining and cooled by sininltaneous aeration after which it is 
either directly filled into bottles, cans or collected in a vat in order 
that it may be thorong-hly mixed. 

The milk shonld be handled as little as possible, since each 
manipnlation not absolutely necessary, means a poorer condition 
of the product from a hygienic standpoint. The producer there- 
fore after straining the milk through cotton strainers should cool 
it and fill it into clean bottles or well-galvanized and properly 
cleaned cans. 

The straining' of milk through straining cloths which have 
been carelessly cleansed by rinsing in cold water, and which in 
most instances fail to answer the purpose on account of their large 
meshes, is, it is to be regretted, in most instances merely a pre- 
tense, which only tends to further spoil the dirty milk. Milk which 
is obtained in an unclean w^ay cannot be deprived of its poor 
qualities by any mechanical means, since the filth dissolves and the 
bacteria pass through the straining cloths and the cotton filter. If 
the accidentally contaminating bacteria are removed immediately 
during the milking (cotton filter in the funnel of milk pail), a con- 
sideral:)le impro^^ement of the milk results. The value of artificial 
cleaning, however, will continue to decrease in proportion to the 
length of time elapsing between the time of milking and cleaning. 
If the cleaning of dirty milk is accomplished only hours afterwards 
at the collecting places and creameries it should be considered as 
direct fraud, which gives the product the appearance of good qual- 
ity without however improving it in any way. In such eases filtra- 
tion and centrifugalization only serve as means of deception. 
Filthy milk which has been subsequently cleaned, must in spite of 
its cleaned condition be considered as spoiled in the sense of the 
pure food law, even if no changes are yet apparent in it. 

In milk control work there are frequent opportunities for 
confiscating dirty market milk, and not infrequently the examina- 
tion reveals that the contamination of the milk consists in dust- 
sized particles and cow manure, all of the same caliber, which in- 
dicates that the milk has been subjected after milking, to a straining 
process which permitted the manure particles which had been dis- 
integrated during the process of milking to pass through the 
strainer. Unstrained milk obtained under filthy conditions usual- 
ly shows the presence of course straw particles, manure, bits of fod- 
der and cow hair. 

After straining, the milk is allowed to flow down over the out- 
side of a double corrugated surface, or a series of parallel horizon- 
tal pipes for the purpose of cooling and simultaneous aeration; 
these surfaces are kept cool through pipes containing running 
water, ice water or brine. Especially practicable and serviceable 
are the so-called round coolers which are provided with spiral 
pipes, covered with tinned-copper sheets, over which the milk runs 
in a thin laver. 



Aeration. 149 

It will be proper to describe here very briefly tlie changes 
which milk undergoes through freezing. The freezing of milk oc- 
curs with remarkable frequency in the winter time, Avhen the milk is 
subject to long transportation. There is no change in the number 
of bacteria which were present at the moment of freezing until 
after the thawing of the milk. There is neither diminution nor 
marked increase. 

According to the data of Vieth, Kaiser and Schmieder, Hen- 
zold, Bordas and Raczkowski, Fritzmann and Mai it may be seen 
that in the freezing of milk a marked separation takes place. Mai 
found that such milk under certain conditions may appear at the 
first glance like ordinary milk, although it is really frozen. Crystal 
needles of ice make their appearance in such milk. If the freezing 
continues layers of ice appear at the sides of the milk cans and on 
the surface, thus enclosing a central fluid portion. The upper 
part of the milk containing the cream layer freezes more loosely, 
in a spongy leaf-like manner. After thawing, the milk has its 
original consistence and its original odor and taste. The peroxi- 
dase content also remains unchanged. 

The milk inspector must consider the separation of milk 
during freezing. In taking a sample, special care should be taken 
to determine whether the milk cans or other vessels already 
contain ice. Frozen milk should not be sold to customers until 
thoroughly thawed. 

The aeration of milk permits the escape of carbonic acid, 
hydrogen and sulphide of hydrogen, and supplies the milk with 
air, so that in all probability the development of certain bacteria 
is checked, which otherwise, if the milk had been filled into con- 
tainers in a warm and un-aerated condition, would have imparted 
to the milk a sharp, disagreeable animal taste and odor ; the milk 
would have been ''suffocated." 

The corrugated surface coolers are especially suitable for 
use in small dairies. 

The cans into which the milk is filled after cooling should be 
tinned in a satisfactory manner. It is to be regretted, however, 
that this is the case only with new cans. The tin covering espe- 
cially on the places where the outside strengthening bands are 
placed, is very imperfect, and after a shorter or longer time 
defects in the lining develop, which soon result in an extensive 
formation of rust. The oxidation of the iron finally results in 
tears and holes which produce deep, sharply circumscribed depres- 
sions in the side of the can in which rust, decomposed milk and 
slime accumulates. 

The transportation of milk in rusty cans, or those in which 
the lining has become damaged, gives it a disagreeable tallowy 
taste. 

Milk should be protected from bright light. Sun rajs and 
indirect daylight may give the milk a talloAvy rancid odor and 



150 Effect of External Influences. 

taste, in the same manner as is tlie case with tlio prolonged action 
of nltra-viok't rays. 

It is important dnring transportation that the vessels he 
closed in an air tight manner, and Avith a cover consisting of 
non-porons material. 

All milk ntensils slionld he cleaned with hot soda solntion, 
with snhseqnent rinsing in fresh pnre water, and if possible com- 
bined with steam sterilization and rapid drying in places protected 
from dnst. 

The transportation of milk shonld be rapid, and where pos- 
sible it shonld be shipped after each milking. 

In creameries the treatment of milk after its receipt shonld 
be principally confined to cooling. This cooling is carried ont in 
deep cooling appliances or donble coolers in which the abstraction 
of the heat takes place throngh water at the point at which the 
milk flows into the cooler, and the lower part is fnrther cooled 
with ice water or with brine. All fnrther manipnlation and at- 
tempted improvements of milk for drinking pnrposes are of no 
nse. Spoiled milk shonld l)e exclnded from the market and not be 
snbjected to renovating processes. 

Tims in some creameries it is cnstomary to clean the milk not 
only by renewed filtration, bnt also by centrifugalization, which is 
frequently done on the supposition that the bacterial content of 
milk becomes reduced through such treatment. This, however, is 
impossible ; on the contrary, such milk often becomes contaminated 
again by bacteria from the non-sterilized centrifuges, and even if 
the milk is centrifuged in a sterilized apparatus only those bacteria 
will be eliminated which adhere to the courser bodies having a 
higher specific gravity (pus, fibrin, filth, casein coagulum, etc.). 

The separator slime therefore contains principally fodder and 
manure bacteria, lactic acid bacteria, species of milk moulds, and 
bacteria of those fermentation processes which take place in the 
residue of milk cans and transportation vessels, and further the 
specific causative agent of mastitis occurring in pus. 

Therefore, although a great number of bacteria are removed, 
the bacterial count through plating of the centrifuged milk dis- 
closes a considerably larger number of bacterial colonies than 
was the case in the milk prior to centrifulgalization, although the 
short time of the centrifuging process does not permit of an 
actual increase of the bacteria. Severin observed an apparent 
increase in bacteria up to 70%. This may be explained by the 
fact that through centrifugalization, bacterial clumps and colonies 
floating in the milk, and the clumps of pus and fatty leucocytes 
which have embodied bacteria, are broken apart, and the bacteria 
are thereb^^ distributed in the milk. Therefore, in spite of the 
removal of considerable numbers, there is an apparent increase. 
This distribution is such that the separator slime and cream 
are considerably richer in bacteria than the skim milk. The 



Bacteria in Cream. 151 



richness of the cream in bacteria may on one hand be explained 
by the fact that large quantities of bacteria are dragged upward 
with the fat globules, and on the other hand by the fact that 
leucocytes containing bacteria, inflammatory products, etc., which 
possess a lower specific gravity, through fatty changes or fat 
enclosures, are taken up with the fat globules into the cream. 

The most important factor in the spoiling of milk in cream- 
eries may usually be found in its being kept for too long a period 
before it is marketed. 



Chapter VIII. 

BACTERIA IN MARKET MILK; THEIR ORIGIN AND 

ACTION. 

Before milking' is commenced tlie udder should be cleansed 
of all adhering- dirt. Cleanliness in milking is one of the most 
important factors in giving the milk good keeping qualities. Sub- 
sequent cleansing through straining, filtration, centrifugaliza- 
tion, etc., is of little purpose after the dirt particles (straw, 
manure, dirt) have once imparted to the milk their soluble con- 
stituents, and an actual inoculation has been accomplished with 
the bacteria of filth. 

The tail of the cow should be tied, in order to prevent bacteria from the skin 
being thrown into the milk by its switching. If left free it may even subject the milk 
to contamination with coarser substances. 

The importance of the effect on human health of bacteria 
which fall into the milk, and which multiply therein when milk 
is improperly procured, is not known, but the thought is at least 
repulsive when it is considered that milk consists of a manure sus- 
pension of a bacterial culture, and on this ground alone absolute 
cleanliness in milking should be insisted upon. In order to attain 
this it is again necessary to provide a properly ventilated and 
well kept stable, as well as milk room. The veterinarians can 
in no way obtain a better recognition of the milk problem than 
by always pointing out to the farmer the necessity of keeping 
healthy cows in properly constructed and well-kept stables, and 
in impressing upon him the fact that the procuring of pure milk 
and its proper handling constitute the fundamental principles of 
a prosperous development of the milk industry in general, and 
not for the milk supply of the city alone. Many farmers, espe- 
cially the small ones, can only be convinced by practical demon- 
strations of the advantages to be derived from proper stabling 
and care, and therefore it is our duty to win over reasonable and 
progressive farmers to the erection of model dairies, and to offer 
to the smaller farmer the aid and advice by which he can improve 
his condition with the least expenditure. Even if nothing more 
than diligence, attention and a feeling of responsibility are aroused 
these alone would mean a tremendous improvement over the con- 
ditions prevailing at the present time. 

It is evident that if no special milk rooms are provided every- 

152 



Procuring- Sterile Milk. ^53 



thing should be avoided during milking which would cause stirring 
up of the dust, such as removal of manure and feeding. 

As long as the milk gland is in a healthy condition the cells 
secrete a sterile product, which becomes contaminated with 
bacteria only in the lowest part of the teats, in their ducts, or 
during the process of milking, etc. 

Bacteria are always present in the lowest parts of the ducts 
of the cistern, as a result of contamination from the litter. These 
bacteria and also those which fall into the milk during milking, 
and the massaging of the quarter, render the procuring of sterile 
milk practically impossible, even when the strictest care is taken 
to prevent as far as possible the subsequent contamination of 
the milk. 

In spite of opposing views, it may be considered proved at 
the present time that the milk in the udder is sterile as long as 
the animal is not affected with diseases of the udder or severe 
general affections. Lister, Miessner, Escherich, Kitt, Tromms- 
dorff, Rullmann, Seibold and others succeeded in procuring abso- 
lutely sterile milk. This, of course, was only in small quanti- 
ties, and drawn with special care, such as washing the udder 
disinfection, protective covers, etc. ' 

_ The first streams of milk are of course always contaminated 
with bacteria (Schulz, Luz, d'Heil) ; the subsequent ones may be 
sterile, but frequently they also may contain bacteria, as confirmed 
by the works of Boekhout, Ott de Vries, Ward, Koning, and 
i^ reudenreich. In practice the procuring of milk with a moderate 
number ot bacteria must be considered satisfactory. Schulz for 
instance, found that the first milk procured contained 55,566 up 
to 97,240 bacteria per c. c, while during the middle of the milking 
It contained only 2,070 to 9,985, and in the last from to 500 
bacteria _ In an interrupted milking, that is, when the milk was 
obtained m four portions, Backhaus and Appel counted in the 
hrst part 170 to 950, in the second 60 to 255, in the third 10 to 70 
m the fourth to 45 bacteria per c. c. ' 

For procuring sterile milk the following measures are recommended: 

washing the udder with soap and water, disinfection with alcohol (Kitt Rolled • 

be carefully drawn by the usual method, which is termed "fisting '' ' ^ 

tains S&int fl'-J '"Y^r cleaning of the udder, covers it with a bag which con- 
t^ScaDe thrnnl ^ S 1 .f '^I* ^'*^°^ ^^ *^^ disinfectant the fluid is allowed 

samples"' Whi.^ntS- ^"f- f^Trommsdorff used sterile milking tubes for taking 
S steVile milkinrt,fhr • f ' r ^' 'flt^^'l ^^^* ^^^^^ ^" t^« "^««t «^^«f"l manipulatioS 
^SeS diiecT S.2 tV'° f'*'''"^ ""^S".^ "'^^^"" sometimes result. Rullmann therefore 
Lf part of thTuddfr ' ''^'*' P^'^^° '^^^" ^°*'' *^^ «^^° «^ ^^' surround- 



]^54 Bacteria in Market ]\Iilk. 



Through such protective measures individual authors obtained 
the followiug results: 

Freudenreich : 200 to 300 bacteria per c. c. 

Szasz: 2 sterile, 11 with an average of about 2,700 bacteria. 

Ilesse : 1,600 bacteria per c. c. 

JNIarshall: 295 bacteria per c. c. 

Lux : to 97 to 6,800 bacteria per c. c. 

Kolle: 80 to 15,000; in 33% of the experiments the counts 
were below 300 bacteria per c. c, 50% below 500, others up to 
800 per c. c. Only 4.7% yielded 700 to 800 bacteria. 

Willem and Minne: 1 to 5 bacteria per c. c. 

AVillem and Miele : to 37, 4 to 218 bacteria, respectively. 

Seibold studied the bacterial content of the milk under the 
most varied experimental methods, and especially under condi- 
tions which correspond most nearly to those prevailing in practice. 

1. Without protective measures. 

2. After soaping the udder. 

3. After soaping and disinfecting with alcohol. 

4. After repeated disinfection Avith alcohol, and procuring 
through sterile milking tubes. 

The poorest results were obtained, as would be expected, by 
the first method, and the best results by the fourth method, with 
which it was frequently possible to obtain completely sterile 
samples. 

The number of bacteria by the fourth method fluctuated 
between and 12, by the third between and 85, and by the second 
between and 434 per c. c. 

The first method produced samples of milk with less than 
10 up to several thousand bacteria. 

Trommsdorff and EuUmann observed in samples which had 
been procured without special precautionary measures, such as 
cleaning of the udder and hands, on an average (96 samples) 
6,700 bacteria per c. c, but only 1,500 bacteria when a thorough 
cleaning of the udder and of the hands of the milker had been 
undertaken. 

Seibold, Trommsdorff and Rullmann found in individual 
cases an enormously high bacterial content even in freshly pro- 
cured milk, the colonies on the plates containing mostly strepto- 
cocci. These samples were obtained from cases of inflammation 
of the udder, and the milk was already contaminated with 
streptococci before leaving the udder. These organisms would 
not otherwise be present in aseptically procured milk (Seibold). 

As it is difficult, even under the strictest conditions, to procure 
sterile milk, or milk with a very low bacterial content, therefore 
in the wholesale production of milk such results are still more 
difficult, and in fact impossible. The milk, immediately after 
leaving the milk canal, becomes contaminated by bacteria which 
have colonized there. Among the bacteria which may be found 



Reduction of Bacterial Content, 155 

in the milk from animals free from ndder affections, and which 
has been drawn under aseptic conditions, the groups of staphy- 
lococci, colon bacteria. Bacillus suhtilis and B. mesentericiis should 
be especially mentioned. Seibold also demonstrated acid-fast 
rods. Rullmann and Trommsdorff found no representative of the 
colon group, but they isolated staphylococci, a few representa- 
tives of spore-bearing species, and especially the anthracoides 
(mycoides) species. 

In ordinary milk production there also come into consider- 
ation an army of air and stable bacteria, which adhere to the 
food, manure and litter, as well as those which vegetate, as 
saprophytes, on the skin of cattle, especially on the skin of the 
teats, and on the hands of the milker, besides those groups of 
bacteria which colonize with special predilection on milking 
utensils and in the cans. 

The number and kind of bacteria found by the different 
authors vary to a considerable extent, depending upon the degree 
of cleanliness used in obtaining the several samples. 

Dean found in milk — 

From filthy cows 9,845 to 17,155 bacteria per c. c. 

From clean dry cows 8,295 to 9,426 bacteria per c. c. 

From cows with dampened skins 640 to 2,350 bacteria per c. c. 

The same work also throws light on the influence of the milk 
vessels. If the milk was collected in sterile milk vessels, 

it contained 355 to 1,702 bacteria per c. c. 

In well cleansed milk vessels. 13,080 to 93,420 bacteria per c. c. 
In dirty milk cans 215,400 to 806,320 bacteria per c. c. 

Russell, in using sterile milk vessels, found 165 bacteria per 
c. c. in freshly drawn milk, while in case of only ordinary cleansing 
there were 4,625 bacteria per c. c. in such freshly procured milk. 
Grotenfeld counted in the milk from well-kept animals, in clean 
stables, only 106 bacteria as compared with 670,000 per c. c. in 
milk from dirty stables. 

The kind of milk can also has an influence. Backhaus con- 
siders enamel cans as the best; tin vessels were found to be 
almost as good, while milk vessels constructed of wood were 
unsatisfactory. 

The work of Koning shows the influence of the bacterial flora 
of the air on the bacterial content of the milk. The author counted 
500,000 to 700,000 bacteria in the stable air, whereas the outside 
air contained only 90,000 bacteria. He found that the volume of 
air between the cows was especially rich in bacteria. Milk which 
is procured in the pasture contains fewer bacteria than stable 
milk. If it is customary to change the straw and also feed shortly 
before or during the milking time, these factors tend greatly to 
increase the bacterial content of the milk. 

If the milk is subjected to the so-called 'improving methods" 
of the most varied kinds, and has to be transported for long dis- 



156 Bacteria in Market Milk. 



tances, it is obvious that when it finally reaches the consumer it 
nmst contain tremendous numl)ers of micr()l)es of various kinds. 
The author counted in the market milk of Munich from 13,000 
upwards to several millions of bacteria per c. c. 

Milk offers to most bacteria which may contaminate it a 
splendid culture medium, their multiplication in it depending 
on the character of the container (cans, flat or open bowls), 
temperature and subsequent treatment. 

Freudenreich, B. Meyer, Cnopf and others conducted experi- 
ments on the influence of cooling on the number of bacteria, and 
established definite proof for the statement made in practice that 
immediate cooling constitutes the best preserving agent for milk. 

According to Cnopf the multiplication at deg. C. was re- 
markablv low, at 12.5 deg. it was 4 to 935 times greater, and at 
35 deg. 2,200 to 3,800 times greater than at deg. C. 

Freudenreich proved that in milk which at the beginning of 
experiments contained 10,000 (accurately 9,300) bacteria, they 
scarcely multiplied when kept for three hours at 15 deg., whereas 
at 25 cleg, they doubled, and at 35 deg. they tripled in quantity. 
After six hours at 15 deg. they numbered 2.7 times, at 25 deg. 
18.5 times, at 35 deg. about 1,300 times more than the original 
number, while after nine hours the number when kept at 15 deg. 
was 5 times, at 25 deg. 108 times, at 35 deg. 3,800 times as numerous 
as in the original count ; and in 24 hours at — 

15 deg. C. the count was 5,700,000, or 613 times 
25 deg. C. the count was 50,000,000, or 5,380 times 
35 deg. C. the count was 570,500,000, or 61,344 times 

The author desires at this place to comment especially on the slight, and somewhat 
problematical value of bacterial counts, not alone because the results of the dilferent 
sowing and counting methods show such enormous differences, but because the entii-e 
system also depends on a supposition of the development of a colony from a single 
bacterium which was previously present, a premise which is open to very serious 
oTijections. If it is considered how many bacteria attach to tenaciously adhering 
threads (sarcina, streiJiococci) , and how many bacteria possess a tendency to proliferate 
in cultural combinations, and to remain together in the relatively sticky material of 
milk, then it becomes apparent that the counted bacterial number represents but a small 
part of the number of bacteria which are actually jiresent in the milk. Of course in 
general the number of colonies developing on the plate represent a certain initial 
point for deducing whether and in what degree a bacterial growth has taken place in 
the milk, but it does not indicate more than the relative age of the milk, since fresh 
milk may also be rich in bacteria, and besides luxuriantly growing as well as slowly 
multiplying bacteria may be present in the milk. 

A better method for the establishment of the actual number of bacteria in milk is 
the one suggested by Skar, which consists of a direct count of the bacteria in a smear 
(see technique). 

Through plating a certain impression is obtained of the kind 
of bacteria occurring in the milk, and corresponding to the growth 
of the colonies and the morphology of the bacteria it is possible 
to draw certain conclusions as to the groups under which the 
bacteria that are present may probably be classified. 

Further deductions as to whether the microbes should be con- 
sidered pathogenic, and whether bacteria are present which confer 



Thennal Limits of Bacteria. 157 

disease-producing properties to the milk through products of de- 
composition, splitting up of proteids, etc., can only be possible 
after an accurate determination of all properties which would 
allow the recognition of the colony as a certain species belonging 
to a large group. 

This determination of the representatives of a group is not simple, and requires 
study and continued experimental work of days and weeks relative to fermentation 
qualities, requirements of growth, pathogenic properties on test animals, ferment-like 
characteristics, etc. These experiments are only of an optional value in practice on 
account of the easy decomposition of milk as a food substance. Nevertheless through 
continued experiments on these problems valuable data and results have been obtained 
increasing our knowledge of the spread of typhoid fever and the methods for combating 
this and other diseases. 

Therefore, it should be aimed to prevent the entrance into the 
milk of directly or indirectly injurious bacteria by procuring the 
milk in a clean and careful manner. Once such bacteria gain 
entrance into the milk and multiply, their recognition and isola- 
tion are too difficult for the practical inspector of milk to consider. 

Milk hygiene can produce practical results only if it is inau- 
gurated at the place of production. 

The pathogenic bacteria of diseases of animals and man will 
not be considered here, and only brief consideration will be given 
to the army of saprophytes which gain entrance to the milk from 
the air, straw, manure and the milk vessels. 

Although from the numerous possibilities of infection of milk 
a definite bacterial flora can hardly be expected, nevertheless, cor- 
responding with the nutritive material of the milk, and the methods 
employed in its storage and transportation, as well as the subse- 
quent treatment, conditions are created which are favorable to 
some varieties of bacteria, while for others they are less favorable 
or even harmful. Through the growth of a certain kind of bacteria 
the conditions may be changed in such a way that the require- 
ments of propagation for other groups are produced. Likewise 
through symbiosis conditions may be developed which are re- 
quired by certain species of bacteria, or under which certain 
species may be destroyed, whereas without symbiosis probably 
neither of the species could exist, since they are dependent upon 
each other. The growth of certain species is therefore dependent 
on numerous influences. 

According to the thermal limits in which bacteria can live, the 
species may be separated into those which thrive at deg. C. (up 
to 15-20 deg.) : psychrophile ; those which thrive at 10-15-40 deg.; 
mesophiles ; and finally into thermophiles, whose thermal optimum 
ranges between 40 to 70 deg. C, or even higher. 

The species of psychrophile propagate even in well cooled 
milk and at low temperature, and at times change its taste. Ref- 
erence should be made here to the Bacillus lactis saponacei and 
the Bacillus sapolacticum, which give a soapy taste to the. milk. 
This defect of flavor is principally observed in cool weather, and 
at the beginning or end of the winter. 



158 Bacteria in Market Milk. 



Siibtilis varieties, mycoid varieties, vinegar bacteria, yeasts, 
PcuiciUium r/Iaucum, mncor varieties and aspergilli also grow from 
to 8 deg. C., as do soil bacteria, fluorescence varieties and bacilli 
which split np proteids (bitter taste of milk). According to 
Kniisel, psychropliile bacteria may be demonstrated in sterilized 
milk, while Bischoff found them in the market milk of Leipsic. 

Bisehoff found that in milk -whieli had been cooled to about defj. C, the bacterial 
number fjvadually diminished from the third to the seventh day; it then multiplied 
rapidly, -ndthout showing a considerable increase in the degree of acidity. A bacterial 
rennet formed, however, and the milk coagulated on boiling. This appeared as early as 
the fourth to seventh day, Avhen the milk was ke)it between G and S deg. C. Frozen 
milk on the other hand keeps for a remarkably long time. 

Kniisel found peptonizing bacteria in sterilized market milk which had been kept 
at S deg. C. ; as a result of their growth the milk had the appearance of soapy water, 
and possessed a bitter taste. 

Therefore, all milk cannot be protected from spoiling by being 
kept cool. The milk must be procured at the start with as small a 
number of bacteria as possible. 

The opposite of these psychropliile species are the thermo- 
philes, which may be actually isolated from the army of accom- 
panying bacteria by a high degree of heat. They continue to grow 
even in temperatures of 70 deg. C, and over (Zettnow), a tem- 
perature at which most of the vegetative bacteria and to some 
extent also spores of the mesophiles and psj^chrophiles are de- 
stroyed. Such bacteria were found not only in hot springs by 
Certes, Garrigon, Karlinski, Teich, Tsiklinsky, but also in river 
water (Miquel, Tieghem, F. Colin, MacFach^an and Blaxall, 
Michaelis and others) ; finally they were found almost everywhere 
by Globig, and in the intestinal content of animals, feces, manure, 
liquid manure, in the soil and upon fodder b}^ Eabinowitsch. 

The thermophile species are not directly pathogenic. This 
group, however, contains several toxin producers, and peptonizers 
of milk. 

Sporulating bacteria which form spores that resist a heat of 
100 deg. C. and over should not be confused with the thermophiles. 
(Peptonizing species, as mycoides, anthracoides, subtilis, mesen- 
tericus and the butja^ic acicl bacilli). Between the ps5^clirophiles 
and the thermophile bacteria lie the large arni}^ of mesophiles, to 
Avhich belong most of the ordinary species of bacteria found in 
market milk. 

Corresponding to their requirements for oxygen they are 
divided into obligatory aerobes, Avhich propagate only in the 
presence of oxygen, facultative anaerobes, which can vegetate 
without oxygen, and obligatory anaerobes, which can grow only in 
the absence of oxygen. 

They may also be divided, according to the substances which 
they attack, into those Avhicli split sugar, proteids and fats, or, 
according to the products which they form during their growth in 
certain media, into acid producers (lactic acid producers, butyric 
acid producers, etc.), or into alkaligenic species and gas producers, 



Period of Incubation. 159 



alcohol producers, bacteria with rennet-like action, pigment pro- 
ducers, slime-forming bacteria, etc. 

The varieties of bacteria which are found in milk under 
general conditions of production, even when conducted under 
special provisions for obtaining clean milk with unusual precau- 
tionary measures (provided that the milk originates from healthy 
animals and is drawn by healthy milkers), are of special interest 
to the milk hygienist. 

These bacteria split sugar and proteids, and attack fat. Ac- 
cording to Fliigge, they are separated into : 

1. Aerobic lactic acid bacteria, which cause spontaneous 
souring and do not form spores; 

2. The anaerobic butyric acid bacilli, and 

3. The aerobic peptonizing bacteria, with remarkably 
resistant spores. 

These bacteria, however, do not propagate uniformly well in 
milk, but they are subject to influences of the medium, which really 
constitutes an elective culture medium for some of the species, 
whereas it is destructive for others. The time during which no 
increase of bacteria can be noted in milk is known as the period 
of incubation (Soxhlet). In fact there may be not only no multi- 
plication of bacteria in the milk, but under certain conditions dur- 
ing the beginning of the incubation there may even be a diminu- 
tion of the bacterial number which is first- found; the bacteria 
present in the milk are subject to the injurious influences of the 
animal secretion; the milk is in the germicidal stage (Koning). 

'Fokker in 1890 was the first to assert that raw milk (he used for his experiments 
goat's milk) must have germicidal properties. He proved that raw milk when inoculated 
with lactic acid bacteria resists spoiling for a longer period than was the case with 
milk that had been boiled. Prior to his investigations however Wolffhiigel and Eiedel 
found in 1886 that cholera vibrios readily multiply in boiled or sterilized milk, whereas 
in raw milk their growth is rapidly checked. As a result of these findings the question as 
to whether milk possesses germicidal properties became the subject of dispute. While 
Freudenreich, Hesse, Pai-k, Cozzolino, Conn, Schenk, Behring, Eullmann and Trommsdorff, 
Eosenau and McCoy, Sassenhagen and Bab claim that milk possesses inhibiting, or even 
destructive properties for bacteria, Richet, Hueppe, Heim, Friedrich, Kitasato, UfPelmann, 
Weigmann and Zirn, Basenau, Schrank, Schottelius, Moro, Heinemann, Rubinstein, 
Stocking, Sommerfeld, Klimmer, Knox and Schorer, and Kuntze express their belief 
against this power in the sense of the bactericidal action of blood serum, and think 
that the germicidal properties exist only towards certain species of bacteria. They 
also believe that the composition of the milk creates favorable conditions for the 
propagation of some of the bacteria, while for others this is not the case, jnst as with 
elective media, some of the less favored species become injured or destroyed by the 
multiplication of lactic acid bacteria and their products. 

The presence of specific germicidal substances (alexins, ambo- 
ceptors, leucins) in special kinds of milk, such as colostral and 
mastitis milk, has been proven by the work of Bauer, Sassenhagen, 
Eullmann and Trommsdorff, whereas the question of the occur- 
rence of these in normal milk has not yet been sufficiently demon- 
strated, although the fact of a diminution of bacteria in freshly 
drawn normal milk has been established by our methods of 
counting. 



ino 



Bacteria in ^Favket ISIilk. 



In order to furnish a few examples, several experimental 
results will be cited from the work of Grimmer. 

Koning found in various samples of freshly drawn milk the 
following numbers of bacteria per c. c: 

Milk : Colostrum : 

2. 3. 

143,000 18,510 

142,000 16,000 



1. 

hnmediatelv 107,000 

after 6 hours 96,000 

after 12 hours 

after 18 hours 120,000 

after 24 hours 

after 30 hours 145,000 

after 36 hours 

after 42 hours 490,000 



155,000 
470,666 



14,700 



1. 

77,000 
71,000 
74,000 



2. 
82",900 
76,400 



56,000 



13,200 115,000 

13,800 115,000 

2,050,000 

106,000 596,000 



800,000 
The slight diminution of the bacterial content of this experi- 
mental series could of course not be attributed to the existence of 
a specific germicidal action, but rather to errors in our methods, or 
to the elective action of media, since the differences are relatively 
slight. 

The results are more apparent in the tables of Eullmann and Trommsdorff : 
Keeping at room temperatnre: 



Teat 


^Hiking 


Imme- 
diately 


1 hour 


2 hrs. 


3 hrs. 


4 hrs. 


5 hrs. 


19 hrs. 


43 hrs. 


fr. r^t. 


1 eginning 


2,400 


2,100 


2,300 


1,900 


2,100 


2, .500 


2,100 


1,200,000 




middle 


1,400 


900 


1,300 


1,600 


1,800 


1,700 


1,300 


1,400,000 




end 


700 


800 


600 


900 


700 


1,100 


700 


500,000 


fr. 1ft. 


beginning 


12,000 


900 


9,000 


7,000 


7,000 


9,000 


6,000 


1,000,000 




middle 


1(1,000 


14,000 


1,800 


1,400 


1,100 


1,600 


1,600 


4.50,000 




end 


3,000 


1,000 


2,400 


2,400 


3,000 


2,700 


2,200 


1,100,000 


M. rot. 


beginning 


200,000 


118,000 


118,000 


10,700 


98,000 


71,000 


33,000 


420,000 




middle 


.35,000 


.56,000 


37,000 


23,000 


38.000 


2S,000 


17,000 


250,000 




end 


13,000 


11,000 


10,000 


5,000 


2,600 


2,400 


900 


1,400,000 


h(l. 1ft. 


beginning 


7,000 


4,400 


4,600 


7,200 


5,400 


5,600 


7,200 


20,000,000 




middle 


60 


400 


160 


240 


ISO 


240 


160 


10.000 




end 


.3,400 


3,000 


3,600 


2,600 


5,000 


2,200 


2,100 


230,000 



In special samples with small bacterial connt the comparison was still more striking: 



Cow No. 


Teat 


At room 


Imme- 


After 


After 


After 


temperatnre 


diately 


one day 


two days 


three davs 


8 


fr. rgt. 


beginning 


160 


40 


16,000 


2,000,000 






middle 


80 


40 


18,000 


16,000,000 






end 


40 


80 


17,000,000 


20,000,000 




fr. 1ft. 


beginning 


11,000 


9,000 


8,000 


40,000 






middle 


1,700 


720 


40 


1,200 






end 


1,300 


600 


800 


18,000 




hd. 7-gt. 


beginning 


120 


400 


2,-500,000 


5,000,000 






middle 


40 


400 


18,000,000 


60,000 






end 


180 


160 


64,000 


5,000,000 




hd. 1ft. 


beginning 


200 


40 


78,000 


5,000,000 






middle 


80 


500 


300,000 


6.500,000 






end 


240 


80 


.50,000 


2,-500,000 


9 


fr. roft. 




600 


360 


2,-500,000 


25,000,000 




fr. 1ft. 




40 


80 


43,000 


4,000,000 




hd. ret 




450 


.500 


2,500,000 


25,000,000 




hd. 1ft. 




40 


240 


9,000,000 


innumerable 



Germicidal Properties. 161 



Trommsdorff and EuUmann conclude from these and other experiments that the 
bacterial content of milk does not increase at room temperature in the first period 
following the milking. "On the contrary in some of the samples inside of the first 
5 to 7 hours a pronounced diminution of the bacterial number was observed, which was 
still more pronounced in the following period so that in a great number of cases the 
bacterial number, after 1, 2, and even 3, and in one case even after 5 days, was found 
lower than directly after the milking. Where there occurred no diminution in bacteria 
the bacterial content remained the same as that found after the milking, during 1 to 3 
days. ' ' 

Milk which has been contaminated with numerous bacteria 
in the earliest periods after milking (dirty milking, filthy ves- 
sels), shows only to a very slight extent the germicidal phase. At 
37 deg. C. the germicidal substances act more rapidly, but the dura- 
tion of the germicidal phase is shortened (Koning, Rullmann and 
Trommsdorff). 

Heating the milk to over 70 deg. C. destroys its germicidal 
properties. 

Bauer and Sassenhagen established the absence of complement in ripe milk which 
gives the impression that in ripe milk the action is elective in the sense that the contained 
substances constitute food for one microbe and poison for another. Of course, it has 
been established for even ordinary kinds of bouillon that, depending on their composition, 
the growth of certain bacterial species upon them has been checked for a time (Basenau). 
The lecithin contents of raw milk must not be left out of consideration; in certain 
concentrations lecithin exerts a strong inhibitory action on bacterial growth. 

Finally the diminution of the bacterial content may be only apparent, as the 
bacteria may multiply through their sticking together in agglutinated masses, thereby 
simulating a diminution, a view which is supported also by Bab for colostral milk. 

After the germicidal action of the milk has worn off the 
various phases of decomposition of milk set in, beginning sooner 
or later, depending on the original contamination of the milk. 
Koning distinguishes seven such phases. 

The fight of the microbes, their harmonious, or again anta- 
gonistic relation to each other, results in a predominance of cer- 
tain species of bacteria in the various phases. 

First (second phase according to Koning, the first being the 
germicidal) the proteolytes split up the proteid bodies of the milk, 
and thereby prepare the soil for the acid producers, which domi- 
nate the further decomposing phase (third phase according to 
Koning) ; the milk coagulates. In the fourth phase the alkali pro- 
ducers partly neutralize the acid again by further splitting up the 
albumoses of the acid milk with the formation of ammonia. Pep- 
tonized casein is also attacked. The principal representative of 
this decomposing phase is the Bacillus fcecalis alkaligenes (Gram 
negative, no gas formation, no indol, no spores, colors litmus milk 
blue). Through neutralization of the lactic acid, certain lactic acid 
bacteria, Bacilhis acidi paralactici, Bacillus acidi Iceiwlacfici and 
Micrococcus acidi paralactici liquefaciens, again regain predomi- 
nance (fifth phase). 

Up to this stage the higher fungi have played a subordinate 
part, although they may have multiplied ; now they appear in great 
masses. The degree of acidity does not hinder their growth. The 
11 



162 Bacteria in Market j\lilk 



Oidium lact'is participates principally in the sixth phase of decom- 
position, although other varieties of moulds, penicillia, and mucors 
nuiy also play a part. The deg-ree of acidity being diminished by 
the oidium, bacteria of the fifth phase again conunence to multiply, 
until the seventh phase is inaugurated through the growth of the 
anaerobic butyric acid bacilli. According to Koning this phase is 
reached at room temperature on about the eighth day. 

Grasberger and Schattenfroh designate the principal representative of this 
bacterial group, the Bacillus saccharobriii/rieus immohilis liquefacicns, a bacillus which 
is large, thick and stubl)y, stains after Gram, and forms spores which are located either 
centrally or at the end of the bacillns. According to Bnrri the bacillus may be most 
readily isolated by boiling the milk for several minutes, and allowing it to ferment at 
37 deg. C. Besides this butyric acid ba'Cillus, other motile forms or bacteria related 
to the first group may be found. 

■ The seventh phase finally passes into the eighth, in which the 
milk changes into a stinking putrid fluid, in which the decomposi- 
tion of the food m.aterial is completed by the proteus, subtilis, 
Bacillus fuorescens, and Bacillus mesentericus, besides mould 
fungi. 

Of these phases of decomposition of milk the first three, espe- 
cially the second and possibly the beginning of the third phase, are 
the most important. 

In these two phases the proteolytes and the rennet formers 
are the first to multiply, causing a partly visible precipitation of the 
casein, but subsequently again dissolving it ; further, the precipi- 
tated protein is immediately partly dissolved when the dissolving 
tryptic ferment is present to excess. Weigmann collects these 
bacteria under the name of casease bacteria. On account of their 
properties of producing peptones from proteid bodies they are 
called peptonizing bacteria. Most of them liquefy gelatin. The 
group of casease bacteria includes a great number of forms of 
bacteria, for instance : 

Staphylococci, small spherical bacteria which occur ubiquitously and in smears 
from cultures appear as grapedike conglomerates. They stain by Gram 's method. They 
grow from deg. to about 40 deg. C, and frequently form at 15 to 20 deg. and over, 
yellowish orange, or lemon-yellow colored colonies. At a low temperature the casease 
enzymes are especially active. In gelatin stab cultures staphylococci first develop a 
nail-like growth; the liquefied gelatin may then dry and at the point of the stab a 
bell-shaped air vesicle forms, or the liquefaction may progress rapidly and a cloudy 
layer of liquid with a sediment of staphylococci stands above the solid gelatin. 

In gelatin plates the small round colony drops into a cup-shaped depression which 
also results from the drying of the liquefied gelatin. Besides the formation of albumose 
and peptones the milk sugar is split up; Lohnis therefore classifies these organisms with 
the lactic acid bacteria. 

The growth of sarcina, which collect into two, four or eight members, etc., is 
similar, thereby forming bacterial clumps of certain forms. They are also Gram-positive. 

On account of their occurrence even in milk drawn in the most cleanly manner, their 
presence in the udder was accepted, and as a matter of fact pathogenic organisms do 
occur in the group of staphylococci, which produce inflammations of the udder. Ordinarily 
however, they only inhabit the milk duct. 

The putrefactive representatives of the proteus varieties should be classified 
among the non-spore bearing casease bacteria. They manifest many forms of growth, 
and include the following representatives: Proteus sopfii, senVeri, vulgaris, miraMlis, 
and fluorescens. 



Putrefactive Bacteria. 163 



They are rod-shaped bacteria, motile, non-spore bearing, and Gram-negative. The 
forms of colonies and characteristics are quite variable, sometimes showing root-like 
extensions, and at other times branching outshoots. 

The most important spore-forming proteolytes originate from forage, hay, stable 
dnst and the stable air, and are collected, under the name of potato bacilli, hay bacilli 
and root bacilli. 

They are small rods up to the size of the anthrax bacillus, with central or terminal 
spores, and are Gram-positive. 

They grow best under aerobic conditions. 

Gelatin is liquefied, milk is precipitated as if by rennet, and is then dissolved. 
In these instances the rennet action is at times more prominent, at other times the action 
of the casease appears more prominently. 

On solid media the colonies have either a wrinkled, slimy appearance, or they are 
dry, with a fine map-like drawing on their surface ; again they may appear like dull 
glass, gray, grayish-white, yellowish to brownish, delicate and profuse. On the borders 
of the culture branch-like shoots or "forms of Medusa heads" similar to the cclonies of 
anthrax (anthracoid varieties) may be seen. 

The more important forms are: 

The Bacillus mesentcricus vidgatus; the potato bacillus (fuscus, graveolens, ruber) ; 
Bacillus liodermes ; Bacillus suhtilis (hay bacillus) ; the mycoid varieties; the anthracoid 
varieties. Bacillus ramosus, implexus, radicosus, tumescens, megatJieriuvi, tyrothrix, etc. 

In fluid media they generally form prolific wrinkled membranes; at times they 
cloud the bouillon or they may grow in long, stringy filamentous masses. 

Some of the varieties also form butyric acid; thus for instance the Bacillus 
Diesentericus changes lactic acid into butyric acid. To this class some of the mycoid 
varieties belong, for instance the Bacillus butyricus Hueppe and the Closti'idium polymyxa. 

Through the growth of these and similar forms, the formation 
of albumose and peptones develops, and the further decomposi- 
tion of the proteid substances is carried out, if possible, with the 
production of end products such as leucin, tyrosin, ammonia, car- 
bonic acid, indol, skatol, methylmerkaptan, sulphureted hydrogen, 
toxic toxalbumins, and ptomaines. 

For the judgment of milk which is considerably contaminated 
with bacteria from litter and forage the increased presence of such 
bacteria is of special importance, since most of them form spores 
which are not always destroyed at the temperature of 100 deg. C. 
and higher. 

The Bacillus prodigiosus, Bacillus fluorescens liquefaciens, 
Bacillus amylohacter, and Bacillus putrificus Bienstock, may also 
split up proteins. Their products vary. 

The bacterial substances which dissolve proteins and split 
them up, exert their action especially in neutral and alkaline ma- 
terial, and they are therefore hindered in their action by the pro- 
ducts of the third phase, the second decomposing phase. 

The lactic acid producers, however, proliferate only after 
the necessary requirements for their propagation have been created 
by the activity of the peptonizing bacteria. 

Through the activity of the lactic acid bacteria the milk sugar 
and other varieties of sugar are fermented to dextro-rotary (ro- 
tates plane of polarization to right) lactic acid, inactive lactic acid, 
and levo-rotary (rotates plane of polarization to left) lactic acid, 
depending on the species of bacteria or the conditions under which 
the special species prevail. 

The splitting of lactose C]oHo.On is accomplished by an inverting bacterial enzyme, 
the lactase, through the introduction of water whereby it is converted into 2C6H12O6 
known as D-glucose and D-galaetose, which by further splitting break up into 4C3H6O3. 



164 Bacteria in Market Milk. 



The lactic acid yield, however, corresponds even in the extreme 
cases only to about 98% of the contained milk sng'ar, as in the mean- 
time, dependini*' on the variety of the lactic acid producers, the 
lactic acid itself is again broken up into simpler acids, acetic acid, 
valerianic acid, succinic acid, and carbonic acid; alcohol, aldehyde 
and possil)ly hydroi»en result besides the lactic acid. 

In spontaneously coagulated milk mostly inactive lactic acid 
is found, or a mixture of inactive and dextro-rotary lactic acid; but 
only in exceptional cases is pure dextro-rotary lactic acid found 
(Gunther and Tierf elder). Kozai mostly found only the dextro- 
rotary polarizing form. 

The lactic acid bacteria may also be considered as ubiquitous 
micro-organisms ; they have been found in straw, hay, fodder, dust, 
feces and in the air. Proliferating in milk they soon adapt them- 
selves to the nutritive medium which at first is not quite suitable 
for their propagation, and finally they form standard varieties for 
Avliich the milk is especially adapted. Through continued growing 
a weakening of the acid forming qualities may develop, and the 
coagulation of the milk may not take place in spite of their growth, 
the bacteria having become ''milk tired." Under these conditions 
they may show other properties, the bacteria rendering the milk 
slimy instead of sour, which is known to be the case with some of 
the lactic acid streptococci. 

The specific lactic acid bacteria are aerobes, or facidtative 
anaerobes. 

Lohnis separates the specific lactic acid bacteria into four col- 
lective groups : 

1. Streptococci. 

2. Plump short rods. 

3. Slender, long, lactic acid bacilli. 

4. Micrococci and staphylococci. 

The most frequent of these are the representatives of the 
streptococcus group. Arranged into wreath-like, shorter or longer 
bodies, the individual meml^ers are characterized by coccus or oval- 
shaped bodies. On artificial media they frequently manifest vacuo- 
lar degenerative forms which change the individual microbes to 
the size of bacilli. Frequently pure diplococcic forms may be found 
wdiich at their ends are mostly pointed in a lancet shape. Strepto- 
cocci grown in milk are composed of individual members mostly 
in the shape of a figure "8" which lie with their long axis in the 
direction of the chain proving them to be streptococci that entered 
the milk after its secretion as compared with the forms from the 
udder. Some of the representatives form capsules but only under 
special cultural conditions, as for instance in blood medium, wdiile 
in other media capsule formation appears to be a constant charac- 
teristic and occurs especially in old milk cultures. 

Most of the streptococpi are Gram-positive. They possess no motility anrl form no 
spores. On solid media the colonies usually remain delicate and small; in fluid media 



streptococci. 



165 



Fig. 24. 



'^- M^^' * 









r\ 






Si. 



the growth takes place either with general clouding, or with the formation of flakes and 
tufts and the bouillon then remains clear. The optimum temperature of the growth lies 
between 10 and 42 deg. C. Most of the varieties are facultative anaerobes. 

Coagulation of milk may take place with acid formation, or in spite of acid 
formation it may not coagulate, or again coagulation may take place with only slight 
acid formation, which in all probability depends on the formation of substances having 
the properties of rennet. 

Gas formation has never been observed by the author, liut it is supposed to occur; 
slime formation is typical of some of the species. 

Lohnis classifies the varieties of streptococci found in milk as : 

1 Those which coagulate milk and form gas: Micrococcus sornthali (Adametz), 
Streptococcus "a" from Kefir (Freudenreich), Streptococcus memelensis (Leichmann), 
Streptococcus caucasicus (Migula). .. , ■ -r, -n 

2 Those which coagulate milk but form no gas: Streptococcus guntlien, Bacillus 
lacticu's Kruse, Bacillus lactis Lister, Lactococcus heijerinh, Bacillus acidi lactici Groten- 
feld, and the streptococci from Armenian buttermilk. 

3. Those which neither co- 
agulate milk nor form gas: 
Streptococcus kefir, Streptococcus 
"h" Freudenreich, Streptococcus 
soya. 

4. Those which neither co- 
agulate milk nor form gas: some 
streptococci of cheese, Strepto- 
coccus inocuus. 

5. Those which form 
slime ; some varieties of the 
Streptococcus pi/ogenes, leuconos- 
toc varieties, Streptococcus hol- 
landicus, Bacterium lactis longi, 
"sticky milk" producers. Micro- 
coccus mucilaginosus, Bacterium 
lactis acidi. 

6. Those which in culture 
form vine or tongue-like shoots. 

7. Those which liquefy 
gelatine. 

It is well known that the 
cultural characteristics of the 
streptococci may readily change : 
a strong acid forming variety 
may lose this characteristic by 
long cultivation in milk, and may 
become a slime producing variety, 
so that the distinguishing feature 
is not absolute. There are transi- 
tory forms between one and the 

other type, and one type at some time may change into another type by changing its 
characteristics. 

Some varieties also belong to those streptococci (collective name streptococcus or 
Bacterium lactis acidi Leichmann), which produce volatile substances and alcohol from 
milk sugar and which at the moment of their development unite into a fragrant substance, 
a so-called fruit ester, which reminds one of the odor of a certain fruit or fruits ; other 
representatives of this variety produce other substances with odor and taste, which may 
be described as straw-like, sorrel-like and especially malt -like. The author never succeeded 
in producing striking odoriferous substances in sterile milk with the streptococci cultures 
at his command. He, however, does not wish to refute from his few experiments with 
about 20 strains from various provinces, the possibility of the production of special 
odoriferous substances by the Streptococcus lacticus. 

Under certain conditions tremendous quantities of streptococci 
may occur in market milk from cows wliicli are affected with .strep- 
tococcic mastitis. Special reference has been made in the chapter 
on affections of the udder, regarding the similarity of these patlio- 












Streptococcus lacticus. 1 X 1000. 



166 



Baetoria iii ]\Iarket Milk. 



Fia-. 25. 



geiiic varieties, to the probabl}' harmless varieties of hictic acid 
jjrodiicers. 

The collective group of the Bacterium ac'idi lacticl is the second 
of importance in the lactic acid group and is also invariably 
represented in milk. 

While the streptococci produoe dextro-rotaiy lactic aciil, among the representatives 
of Baciirium acidi lactici there are those which produce levo-rotary lactic acid, 
yince the growth of both species of bacteria depends on the temperature and the method 
of keeping the milk (in a shallow bowl or iu a deep vessel), therefore under certain con- 
ditions whereby the Bacterium acidi lactici has better chances for vegetating (aerobe, 
optimum at about 37 deg.), it produces levo-rotary lactic acid and in souring in deep 
vessels (the Si reptococcus lactis acidi is a facultative anaerobe and grows well at 20 deg.) 
it produces dextro-rotary lactic acid. These results have been eonlirmed by the observa- 
tions of Conn and Esten. The findings of 
Heinemanu, Thiele and Plolling that at incuba- 
tor and room temperature, iu milk drawn under 
specially clean conditions, "d-lactic acid" is 
formed only at the beginning, are of interest. 

Against the practical ntilization of these 
observations, namely the conclusion that the ex- 
elusive presence of dextro-rotary lactic acid is 
dependent on the specially clean procurance of 
the milk, are the investigations of Pere and 
Harden, who claim that the nature of the 
acid formed depends not only on the producer 
but also iu the case of the same producer on 
the character of experimental procedure ; thus 
for instance one and the same strain of Bac- 
teriiim coU produced lactic acid showing opti- 
cally different properties when cultivated under 
different conditions, acirobieally or anaerobi- 
eally, etc. 

The Bacillus acidi lactici 
(Hueppe) group also does not rep- 
resent constantly uniform species, 
but it is a collective name "vvhich 
unites all bacteria with especially 
strong acid forming properties that 
lean towards the colon and espe- 
cially to the aerogenes species. 

The Bacterium acidi lactici Hueppe and the BaciJhi.'i pneumonia' Friedlander are 
similar to the coli-aerogeues species. They are jjlump, mostly Gram-uegative, from cocci 
to short roils in appearance, forming individually longer rods and short thread-like 
filaments; they grow luxuriantly, forming moist or almost dry indented colonies with a 
slimy or jelly-like consistence. In dextrose media usually a strong acid formation 
takes place. On potatoes the growth is either luxuriant with gas bubbles, or brownish 
and thin, or transparent. The odor varies, being either disagreeable or pleasant, or at 
times even odorless. From this description it may be seen that a great number of 
bacteria are united in this group which are classed by Lohnis as follows: 

1. Ty|ie of the Bacillus acidi lactici Hueppe. 

Gas formation with milk coagulation. To these belong the Bacillus aiirogenes, 
Bacillus "a" Guillebeau, Bacillus "h" Freudenreieh, Bacillus lacvolacticns. Bacillus 
acidi lactici Gortenfehl, also the lactic acid bacilli of Fokker and others which possess 
differing characteristics, as for instance the formation of esterlike odors, cheesy odors, etc. 

2. Milk coagulation without gas formation. Bacillus limliaium (acidi lactici) 
Marpmann, without special tendency to deep growth. Bacillus acidi aromaticns, Bacillus 
granulo.mm, crenatum, spirans and ramifcans (Weiss) and others. 

3. Gas formation without coagulation of milk, producing white, circumscribed, 
hemispherical colonies, as for instance the Bacillus pneumoniae Friedlander. 

4. Neither gas formation nor coagulation. 




Ivepresentatives of the cnli-aevogeiies 
group, from a culture. 1 X 800 (Bac- 
terium phlcgmasiac ttbcris, after Kitt.) 



Cheese Bacteria. 167 



5. Neither gas formation nor coagulation, but slime formation is present, for 
instance the Bacillus capsulatus, Bacillus viscosus, Bacillus capsulatus mucosus, Bacillus 
laciis pituitosi, Bacterium ozaena. 

6. The tendril-shaped colony forming Bacillus aerogenes capsulatus. 

7. Without gas formation, but with liquefaction, for instance the Pneumobacillus 
liquefaciens bovis. 

A decisive separation of these types cannot be strictly ac- 
complished anywhere in the entire group. Each type has indi- 
vidual or several representatives which show transitory tendencies 
towards one or the other group, and the entire group is closely re- 
lated to the colon aerogenes group, but in the latter, there are no 
such pronounced lactic acid formations. The colon group is motile, 
the aerogenes group non-motile. While the colon bacilli form indol 
and split up proteids, these properties are absent in the aerogenes 
group. Milk is coagulated with gas and acid formation, in which 
the casein usually remains on the surface of the pressed-out serum 
in the form of a spongy coagulum. The milk receives at the same 
time an unpleasant, slightly offensive odor, and a salty, bitter taste. 
Some varieties change the milk in this manner without the special 
changes being perceptible. The several groups adapt themselves 
very rapidly to their surrounding conditions, for instance to the 
cultivation on cabbage or turnip media, and when transferred to 
milk they impart to these the well-known changes of taste. 

Both bacteria are found in the intestines of sucklings 
(Escherich). 

It is an important fact that most bacteria of this group are 
destroyed in a short time at 65 deg. C, so that their occurrence 
in pasteurized milk (in bottle pasteurization) may be an indication 
that the heating to which the milk has been subjected was 
insufficient. 

According to De Jong and Graaf some varieties of the colon 
group resist heating to 70 deg. C. for a short time. 

The slender '' cheese bacteria" of the third group of the lactic 
acid producers are again divided into : 

1. Those coagulating milk with gas formation, for instance 
Bacterium easel (Freudenreich), Bacillus caucasicus of Kefir 
(Freudenreich) ; 

2. Those coagulating milk but with no gas formation ; 

3. Those producing gas but no coagulation ; 

4. Those showing neither of these characteristics; 

5. Those producing slime ; 

6. Those growing in tendril-shaped colonies. 

The bacteria of this third group are almost invariably non- 
motile, and sporeless, mostly without capsules. They are Gram- 
positive. The fermentation of sugar varies. In milk they mostly 
form levo-rotary lactic acid, while the other two varieties are rarely 
produced. Some peptonize proteids ; their growth is favored more 
by aerobic than by anaerobic conditions. 



168 Bacteria in Market Milk. 



The bacteria do not grow well in milk Imt they are found in 
cheese, in the oriental varieties of sour milk and in sour food. 
These bacteria are of only slight importance in the ordinary lac- 
tic acid fermentation. They prefer higher temperatures and pro- 
duce fermentation only in the absence of oxygen, although their 
growth is prolific even in the presence of oxygen. 

As representatives of this group the Bacillus pants fermentati 
occurring on sour bread should be mentioned, and the Bacillus 
delbriicJxi found on sour food. 

Some representatives of these "cheese bacteria" are capable 
at high temperature (40-50 dog. C.) of producing and withstanding 
large quantities of lactic acid, up to 1.5%, and even to 2 to 2.5%. 

Lohnis classifies the staphylococci as the fourth most widely 
distributed bacterial group of the lactic acid producers, but on ac- 
count of their peptonizing characteristics they might better be 
considered with the casease bacteria of Weigmann. Their proper- 
ties have already been described during the discussion of bacteria 
of the first decomposing phase. The staphylococci may also be 
separated into : 

(a) Those coagulating milk and liquefying gelatin. 

(b) Those which only liquefy gelatin, 

(c) Those which only coagulate milk. 

(d) Those which posses neither of these properties, 

nor form slime, produce gas, nor form tendrils. 

The species nientionerl by no means exhaust the number of species and groups 
which are capable of producing lactic acid. Thus the anthrax bacillus splits up sugar 
and starch into lactic acid, and also forms acetic acid (Napias), and formic acid 
(Iwanoff). Feiuberg demonstrated for the diphtheria bacillus the capability of splitting 
up milk sugar with the formation of alcohol, aldehyde and volatile as well as non-volatile 
acids. The bacillus of malignant edema, according to Kerry and Frankel, in the 
anaerobic fermentation of grape sugar, produces ethyl alcohol, formic acid, butyric acid 
and lactic acid ; cholera vibrios and related organisms form lactic acid ; for instance 
the vibrio of Asiatic cholera, the Vibrio proteufs (Fiukler and Prior), Vihrin massanah, 
rihrio clanubicus and others form levo-rotary lactic acid, the vibrio of Deneke forms 
dextro-rotary and J'ihrin hernJinensis produces an inactive lactic acid. The formation of 
these lactic acids, however, does not depend on the bacillus alone. 

The Oidium. lactis, a milk mould, and others, are also capable 
of producing lactic acid from milk sugar. Some of the lactic acid 
forming varieties are rare in milk, others may accustom themselves 
to milk so rapidly that they form the typical acidifying flora, the 
presence of vdiich under certain conditions may be desirable since 
by their multiplication the vegetation of the harmful peptonizing 
bacteria and of the producers of butyric acid is inhibited. 

With this we leave the most important varieties of bacteria 
whicli are responsible for the normal spoiling of milk, and will 
briefly discuss those varieties of microbes belonging to the liacte- 
riology of milk and milk production which always occur in market 
milk. 

Milk also invariably contains butyric acid bacilli. Their pre- 
dominance is inhibited by the lactic acid fermentation. 



Butvric Acid Bacilli. 



169 



The specific butyric acid bacilli are obligatory anaerobic or 
facultatively anaerobic, that is they thrive best in the absence of 
oxygen; there are, however, aerobic bacteria which are capable of 
forming butyric acid, for instance several of the above-mentioned 
peptonizing varieties, the hay and potato bacilli, which without 
specially attacking the milk sugar, form butyric acid from the 
products of the split proteids. 

The individual varieties show varying properties toward the different kinds of 
sugars, as well as toward the formed by-products, as butyl alcohol, isobutyl alcohol, 
formic acid, acetic acid, propionic acid, valerianic acid, carbonic acid, hydrogen, etc. 

The obligatory butyric acid producers are rods, chains or threads, with either a plump 
or a slender form; they possess oval or roundish polar or central spores. The bacteria 

Fig. 26. 




Blackleg bacilli. 1 X 1200. 
(After Friedberger & Frohner.) 

frequently form so-called Clostridium forms, and especially in starch-containing media 
they take up granulose ; therefore certain parts of their body or even the entire bacillus 
may be stained blue with iodide of potassium. 

The representatives of this group are known to pathologists 
as producers of blackleg, gaseous phlegmons, malignant edema, 
bradsot, botulism, and tetanus. These bacilli at times are capable 
of energetically forming butyric acid, and at other times less in- 
tensively; at the same time peptonizing ferments (tryptic) are 
formed, which become active in the absence of acid. 

Generally motile and non-motile forms of butyric acid bacilli 
are distinguished in milk. The latter form, of the granular Bacillus 
saccharohutyricus is considered by Grasberger and Schattenfroh 
as a developing form of the motile, spore-forming variety which 
takes up granulose, forms toxins, and attacks lactic acid. 

According to their properties they may be divided into those 
which form butyric acid principally from certain carbohydrates, 



170 Bacteria in JMarket Milk. 



as for instance the blackleg- bacillus, the non-motile l)utyric acid 
bacillus (Grasberger and Scliattenfroli), and the bacillus of gaseous 
jihlegnions (Pninkel). The others are producers of putrefaction 
and split up the proteids into forms from which volatile fatty acids 
develop. 

Obligatory fat-splitting bacteria may also, although less fre- 
quently, be found in milk, as for instance the Bactridhnn lipolyti- 
ciini (Huss), through the growth of which the milk acquires a rancid 
taste. The Bacillus jinoyesce}is, Bacillus produiiosus and others, 
for instance certain mould fungi, may also produce fat-splitting 
enzymes. 

Actinomyces form the transition organisms which lead from 
bacilli to higiier fungi. These fungi form long threads with true 
branchings. Widely distributed on grasses and especially grain, as 
Avell as in the soil, they are of course also contained in manure and 
litter, and may occur in milk and milk products, butter or cheese, 
and multiply therein. 

As is the case with all milk bacteria, among the actinomyces 
there may occur forms which under certain conditions such as 
wound infection, produce diseases (chronic suppurations). 

Some varieties of bacteria classified by Lohnis as lacto-bacilli, 
as for instance a microbe isolated by Chatter jee from "Dadhi," 
(Indian sour milk) Slrcpfofhrix clacllii and several bacteria which 
were found in Mazun, Yoghurt and in the Montenegrin ''Grusa- 
Adna" and ''Kysla varenika," appear from their morphological 
properties, to belong to the streptothrix (actinomyces). 

Finally it will be advisable to discuss the higher fungi, yeasts 
and moulds which occur in milk. They cause a slight alcoholic fer- 
mentation of the milk; not all varieties however attack the milk 
sugar, although a great number of the most varied fungi and 
yeast are found in milk, for instance penicilia, mucors, aspergilli. 

By far the most frequent fungus in milk is the Oidium lactis, 
under which name are collected all mycelial forms, whose radiating 
mycelia carry hypha?, that break up into small, rectangular, cylin- 
drical members, the so-called oidia, which in proper media again 
grow out into a mycelium. The growth of the oidium varieties 
gives the surface of the cream layer a yellowish-white, velvety, fre- 
quently wrinkled appearance, which later may take up a glassy 
transparent appearance. 

Oidium lactis causes fermentation in sugar-containing media, 
and develops carbonic acid and a slight amount of alcohol. A. 
pleasant aroma results from cultures in dextrose but in the split- 
ting up of saccharose, lactose and maltose, an intensive cheesy 
odor develops. Besides sugar, proteids if present are split up. 
Therefore in the zones of growth of the oidium varieties a pepton- 
ization is manifested in the milk. Lactic acid is also produced and 
later again disappears. 

Besides the oidia there may also be found the closely related 



Buttermilk. 171 



moniliar varieties wliic]i at times grow like the oidia with a typical 
mycelium, at other times it is a sporulating fungus (Mon. varia- 
bilis; candicans, etc.) ; also varieties of mycoderma, which always 
multiply in a longitudinal direction, by the protrusion of daughter 
cells which continuously bud out new daughter cells and these con- 
tinue to grow in the already established direction. 

In the preparation of certain fermented forms of milk which 
are frequently desired in certain sour milk preparations, the sporu- 
lating fungi which multiply in all directions of space through 
sporulations are of importance. 

Through their activity, that is through the formed enzymes, 
the milk sugar is split up into dextrose and D-galactose, and ulti- 
mately the dextrose is split up into alcohol and carbonic acid. Milk 
may contain saccharomyces varieties, which form endospores and 
torula varieties, whose daughter cells no longer separate in all 
directions but arranging themselves into rows form mostly spheri- 
cal shaped or sausage-shaped buds, and have no endospores. 

Milk Preparations, Buttermilk, Etc., Produced By Special 

Fermentation. 

Many varieties of foreign buttermilk or sour milk have recent- 
ly become known in this country. Especial dietetic value is attri- 
buted to them ; as to whether they possess advantages over our own 
buttermilk or not is not yet known. The author believes that our 
native buttermilk possesses the same advantages provided it is 
prepared with the same care as the buttermilk known as Yoghurt, 
Mazun, Leben-raib, Gioddu (Sardinia), etc., besides many of the 
foreign milk preparations which are marketed under various names 
frequently contain nothing more than native varieties of our lactic 
acid streptococci and certain cheese bacteria. 

Yoghurt is the buttermilk of Bulgaria. It is prepared by 
adding to the milk the ferment maya after the milk has been boiled 
down to half of its volume, and cooled to about 50 deg. C The mass 
is then kept at 40-50 deg. and after 10-14 hours the Yoghurt is 
finished. The necessary fermentation temperature is obtained 
through cooking boxes, or covering the hot vessels with non-con- 
ducting material (woolens). Weigmann in his "Mycology of 
Milk" quotes the verbal information of Kostoff from which it may 
be seen that the concentration of the boiled milk is not always car- 
ried out in Bulgaria, but a ferment (Maya, in Bulgarian Podkwas- 
sa) is stirred up with a small amount of boiled milk, which is added 
to the milk and kept at 45-48 deg. C. If a sufficient amount of fer- 
ment is added the Yoghurt is finished in from 31/4,-4 hours. It is 
cooled for 1-2 hours, and may then be consumed. 

According to information obtained by the author there is an- 
other method of preparation in Bulgaria which is carried out by 
the dairymen, and produces a primary Yoghurt. According to the 
description of Marcoff, to whose kindness I am indebted for this 



172 ^lilk Preparations. 



information, the dairymen take a widely grown herb (name was 
unknown to Marcoff), which they crush up in small linen sacks. A 
small quantity of the juice is then squeezed out and added to the 
raw milk, whereupon without further treatment tli(^ coagulation of 
the milk takes place within a few hours. From this preparation 
the Yoghurt then may be prepared. 

According- to this description the primary juice action may 
be attributed to a vegetable rennet. With the plant juice other 
bacteria also enter into tlie milk, the product of which is represent- 
ed by their elective cultivation. 

As effective bacteria in the production of Bulgarian butter- 
milk are considered : 1. A lactic acid long rod, which belongs to 
the. acidophilic bacilli of the intestinal tract: the Bacillus hidfjari- 
cus. This is the aroma producer of Yoghurt. The Yoghurt also 
contains streptococci of lactic acid; veasts are not desirable (see 
Table IV). 

The same conditions exist in the Armenian Mazun, a very 
aromatic preparation of buttermilk, which is prepared from boiled 
cow milk, buffalo, sheep or goat milk. Diiggeli demonstrated that 
satisfactory Mazun (Tartaric Katycli) contains principally three 
varieties of microbes, a streptococcus, a long rod-shaped lactic 
acid bacterium, and yeasts, the activity of which produces the 
aromatic bodies, besides a slight amount of alcohol and carbonic 
acid. 

Lelien-raib, according to Rist and Khoury contains five micro- 
organisms, among them being two varieties of yeast and two lactic 
acid producers. The buttermilk is prepared in a similar way to 
Kefir, by using cow, buffalo or goat milk. 

Kefir has been used for a much longer time and therefore is 
more generally known. It contains alcohol and is very rich in car- 
bonic acid; it has a pleasant, slightly acid odor and taste. It con- 
tains the milk proteins split up to some extent (Hueppe) in ad- 
dition to alcohol and carbonic acid and a slight amount of glycerin, 
succinic acid, butyric acid and acetic acid. 

Kefir is best prepared from skimmed milk, since in full milk, 
cream clumps may readily result and the Kefir thereby becomes 
rancid, which diminishes the consuming value. According to Freu- 
denreicli the fermentation is principally produced by four varieties 
of organisms which include yeasts, two streptococci varieties, and 
one microbe described as the Bacillus caucasicus. 

The yeasts are the Tonda kefir and Saccharomyces frar/ilis, 
both of which ferment lactose. Investigations which have been re- 
cently conducted by Kuntze showed that the bacteria of Kefir con- 
sist of an aroma-forming rod which produces casease and alcohol, 
and a lactic acid long rod which at first acidifies the milk and then 
renders it alkaline. They are the Bacillus esferificans Maassen and 
the Bacillus licfir classified by Kuntze as belonging to the group of 
butyric acid bacilli (cited by Weigmann). These bacilli inoculated 



Kefir. 173 

into milk, together with ordinary lactic acid producers, living in 
symbiosis with yeast, form granules which grow to raspberry sized 
clumps and nodes. Sponge-like masses of ruffle-like appearance, 
the so-called Kefir kernels result, in which are included the neces- 
sary varieties of microbes. In dried condition these kernels are of 
the size of millet seeds, but after treating with warm water or warm 
milk they swell and proliferate in the milk up to the size of a fist. 
The small young kernels are the best, as the larger readily degen- 
erate, become slimy and crumbling as compared with the elastic 
granules of more recent development. In order that they may again 
produce good Kefir they must be subjected to treatment by 
washing, drying in the sun, etc. The Kefir kernels may be 
purchased. 

The origin of the Kefir kernels, that is the microbe colonies 
A\ hich are clumped in the kernels, is not known, but the primary de- 
velopment may have some connection with the method of ferment- 
ing milk in containers made out of goat skins. 

If it is desired to prepare Kefir it is necessary to first obtain 
the kernels which may be purchased. The Kefir kernels are 
allowed to soak in boiled or lukewarm water, and then they are 
transferred several times (3 to 5 times) from one warm milk into 
another, the milk being poured off every 3 or 4 hours. 

The utilizable Kefir kernels increase in size during this time 
through further swelling, and as a result of becoming lighter in 
weight through absorption of carbonic acid they rise to the sur- 
face of the milk, whereas kernels in which one of the varieties of 
microbes for some reason or other became destroyed and degener- 
ated remain on the bottom of the vessel. If the degenerated variety 
of microbes recover through longer treatment with raw milk, and 
if the proper relation of symbiosis again appears, then these ker- 
nels are satisfactory for the production of Kefir. This condition is 
manifested by the kernels rising to the surface of the milk after 
some days. 

If a tablespoonful of these kernels is added to about one-half 
liter of milk and this is allowed to stand for from 8 to 12 hours 
at 14 to 18 deg. C, with frequent shaking, then a primary or mother 
Kefir is obtained, from which through further fermentation in 
corked bottles the Kefir may be prepared ready for use. 

. The ''millets of the prophet," the Kefir kernels, are strained 
through a sieve, and the homogeneous fermented milk is filled into 
bottles, or from the strained fluid a considerable quantity is poured 
into a bottle, to which boiled milk cooled to about 20 deg. C. is 
added. The bottle is then closed and allowed to continue to fer- 
ment for from 24 to 28 hours, at from 12-15 deg. C. In this 
process the casein and serum separate but may be readily homo- 
genized by shaking. The Kefir is then ready for consumption, 
and represents a thick, sour, aromatic fluid of a pungent taste, 
with a remarkable nutritive value. 

A similar product is prepared by the nomadic population of 



174 ^lilk Preparations. 



Southern Eussia, Siberia, and Central Asia, ^vlliell represents a 
milk wine made from the milk of mares and asses, and which is 
known by the name of Kumys. In the preparation of Kumys, 
alcohol and carbonic acid fermentations are the principal processes. 
After long fermentation Kumys contains up to 2% of alcohol and 
1% or more carbonic acid. 

Bacteriologically Kumys is of similar composition to Kefir 
containing- yeasts, lactic acid, streptococci, and the Bacillus kumys 
(Schipin), which is a facultative anaerolnc microbe which splits up 
milk sugar with the formation of lactic acid and alcohol and 
peptonization of the proteids. These act together and form 
after several days a delicious drink of white color, and creamy con- 
sistence. Special varieties of milk, containing much sugar, are 
best adapted for the preparation of Kumys but cow's milk is the 
least desirable. 

Gioddu, the buttermilk of Sardinia, is prepared from boiled 
milk cooled to about 35 deg. C. To four parts of milk one part of 
old Gioddu is mixed, the Gioddu being added to cow, sheep or goat 
milk. The fermentation is produced by the Bacillus sardous in 
s^nnbiosis with the Saccliaromyces sardous. According to Grisconi 
the Bacillus sardous belongs to the streptobacilli. 

The preparation of buttermilk constitutes an important branch 
of the utilization of milk in all countries. In northern Bavaria 
the milk is usually set in large earthen pots and allowed to undergo 
voluntary fermentation. In southern Bavaria and in the Bavarian 
forests the ''fall milk" is utilized for the preparation of the 
*'sour soup." By keeping buttermilk and continually adding sour 
skimmed milk to it a fermenting product is obtained which is 
thickened by the removal of the whey (Herz). 

In Sweden and Norway a milk product is known under the 
name of "thick milk" (Tatmjolk), which is produced by slime and 
lacticacid producing bacteria which vegetate on the leaves of the 
butterwort (Pinguicula vulgaris). 

The leaves of this plant are placed on the bottom of the milk 
vessel and milk poured over them, whereupon the milk becomes so 
thick in several hours that it must be cut with a spoon or knife in 
order to be taken into the mouth (Weigmann). New milk may 
be inoculated with the residue of old milk. 

The necessary preparations of bacteria for the making of 
special forms of popular buttermilk may at the present time 
be purchased in the market. In using any of these ' ' ferments ' ' the 
directions for use should be carefully followed, since at a tempera- 
ture either too high or too low an overproduction of undesirable 
bacteria may readily take place which would make good results im- 
possible. Even if the directions are carried out most accurately, 
the propagation from milk to milk may be a failure since the biolog- 
ical properties of the bacteria are not absolutely constant; the 
microbes ''grow wild" and their pleasant qualities are lost, or they 
may change, assuming undesirable properties. 



Table IV. 



// j I 



:fe \\ 







\ 









/i?i' 






^ ^5 



A ) /^ 



i 



'^yl 



1/ 






Butyric acid bacilli in boiled milk, kept for two days at 37 °0 
1X1200. 



B. 



M 



V 



\J 



CiJ? V;^ /^ J^li \ "^ 



\^ 



Film of Yoghurt. Ba«7/«.f hulgaricus and lactic acid streptococci 
trram-safranin stain. 1 X 1200. 



Ernst, Milk Hygiene. 



Bitter Milk. I75 



. Porcelain vessels and bottles made from glass free of lead are 
most suitable for the preparation of buttermilk, since the butter- 
milk may extract lead from enameled earthenware and from pots 
whose glazing contains lead in its composition. 

According to Chlopin . 84 mg. of lead was extracted from 100 
gm. lactobacillin-buttermilk ; in a second portion (300 gm. butter- 
milk) which was five days old, the amount reached 7 . 86 mg. Briick- 
mann obtained similar results : 300 gm. of ordinary buttermilk con- 
tained after four days 4.2 mg., and after six days 5.7 mg. of lead, 
when this product had been prepared in pots with lead-containing 
glazing. 

Defects of Milk. 

Bacteria produce certain modifications in milk which partly 
on account of their frequency are designated as normal processes, 
or again others appear which are less frequently observed, occur- 
ring only under special conditions and therefore are known as 
milk defects. The modification, as has been seen, may be even 
desirable, as for instance in cream souring and cream ripening 
for butter making, or in the preparation of Kefir, Yoghurt, and 
buttermilk, or it may be undesirable and injurious, spoiling the 
milk, and having a disturbing influence on milk utilization, espe- 
cially in its use for drinking purposes. 

Among the changes in milk there are those which appear fre- 
quently, and others which are very rare. 

Under conditions which favor propagation of peptonizing 
bacteria (staphylococci, sarcina, anthracoides, mycoides, mesen- 
tericus varieties, fluorescens, pyocyaneus, etc.), the milk attains a 
bitter taste. 

For instance if uncooled milk is filled into cans which are 
immediately closed it ^'suffocates," acquiring a strong stable 
odor which may even reach a putrid character, causing a solution 
of the casein by reason of which the milk no longer coagulates ; or 
the appearance of a bacterial rennet produces a rennet-like pre- 
cipitation of the casein, and the milk coagulates without turning- 
sour. It is '' sweet-coagulating. " By the action of peptonizing 
micrococci, which in part are psychrophilic the development of a 
bitter taste may occur in thoroughly cooled, and even in excessive- 
ly cooled milk. The bacteria of the colon group when the condi- 
tions of their propagation are favorable may produce an odor in 
milk ranging from aromatic to rancid, or some varieties of this 
group which have grown on mangels may confer the odor of man- 
gels to the milk. 

A bitter taste in milk may also occur from the feeding of foods 
containing bitter substances, thus for instance from the feeding 
of lupins, vetches, mangels, camomile, beet leaves, wood-fern, raw 
potatoes, mouldy or spoiled hay, straw, etc. It may however be 
accepted that the development of a bitter taste in milk usually 



176 Defects of Milk. 



results from its contamination with varieties of bacteria vegetating 
on food substances, which enter into the milk directly from the 
stable air or indirectly with the manure and litter. They then con- 
vey to the milk this altered taste. Experiments to confirm these 
views have been undertaken quite recently by Weigmann and 
Wolf (Kiel). 

Defective flavors are frequently present in milk. 

Of 1,000 retentions made during 1909 in Munich, 90.50% were 
on account of souring, 14.6% on account of soapy taste, 18.25% 
rancid, 2.19% fecal contamination, 8.76% oily, 1.46% bitter, 
2.92% granular, 2.19% sweet-coagulating, and 1.46% on account 
of slimy conditions. 

Representatives of the colon-aerogenes group may actually be 
cultivated imtil they become aroma producers if they are allowed 
to grow for instance upon media made from rape leaves. If an 
adaptation of these and other bacteria to the ingesta within the 
gastro-intestinal canal is admitted, then an acquisition of certain 
other properties, depending on the consumed feed, is readily 
conceivable. 

AVeigmann and Eitland and Jensen demonstrated such "rape 
bacteria" in milk having a rape-leaf taste; the milk at the same 
time had a stale taste and an odor of dish-water. The author ob- 
served a distinct phosphorus taste in cases in which the milk was 
placed without being cooled into unclean or poorly cleaned covered 
cans. 

Animal and fecal odors result when freshly drawn milk is 
placed into covered cans w^ithout airing and cooling. In these 
cases the vegetation of anaerobic and facultative anaerobic bacteria 
may play a part, and the temperature may have an effect on the 
bacterial elective conditions. The milk attains a taste like animal 
viscera if it contains bacteria of the mycoid, megatherium or fluor- 
escens group. 

Fishy taste of milk may result from pasturing cows on marshy 
meadows which have been inundated. In these instances the pres- 
ence of various other varieties of bacteria should be taken into 
consideration. 

The multiplication of the BaciUus lacfis saponacei (Weig- 
mann) and the Bacillus sapolacticum (Eichholz), produces a soapy 
condition of the milk. The milk attains a sharp, rancid, soap-like 
taste, and when cold it reminds one of valerian ; in a warm state 
it has a sharp, soapy odor. In shaking such milk a fine, vesicular, 
persistent, tenacious foam results. The change appears in thor- 
oughly cooled and excessively cooled milk, and in the cold season 
of the year and in cold rainy summers the bacteria are psychro- 
pliilic, originating from the feed and straw. 

The Bacillus lacficus saponacei grows well at room tempera- 
ture, liquefies gelatin, and produces a slight yellowish shimmering 
coloring matter ; the growth is aerobic. The Bacterium sapolacti- 



Blue Milk. 177 

cum grows similarly. It is not supposed to liquefy gelatin. The 
nutritive media become fluorescent. 

Tlie propagation of butyric acid bacteria causes rancidity of 
milk, as does likewise the multiplication of bacteria which spilt up 
fats, for instance the Bacterium lipolyticum. 

The appearance of the milk defects here mentioned may 
sometimes be confined to the product of a single individual in the 
stable. The milk of one or of several cows may manifest these 
defects which may be retained persistently in spite of changing 
the feed and disinfecting the stable. 

Weigmann mentions a case in which, with uniform feeding and care of the animals, 
the milk of only one cow developed a fishy odor, and to such a marked extent that the 
milk of the entire herd became fishy (possibly the udder of this cow was diseased). 

The same author mentions another case which occurred on an estate in northern 
Germany. In that instance the milk of the Montavania cows in the stable was constantly 
rancid, whereas the milk of the Holstein cows was faultless, although the animals were 
all kept under the same conditions. The Bacillus lipolyticum was found to be the dis- 
turbing bacterium. It is noteworthy that the milk of the Montavania cows was frequently 
bloody at the same time. Therefore it is possible that the elimination of the aroma 
bacteria took place from the affected udders, that is, the same bacterium was also the 
cause of the inflammation of the udder. However, it is more likely that through the 
secretion of the affected udders conditions were established in the milk from the Mon- 
tavania animals which favored the propagation of the Bacterium lipoli/ticum in the 
milk, or probably the bacteria were present in the milk cisterns of these cows as harmless 
saprophytes, and the blood content of the milk may be attributed to some affection of 
the udder (yellow garget), which had no connection with the cause of the rancid milk. 

It has also been proved that other changes in milk may per- 
sistently occur in the secretion of certain individuals so that it 
appears as if the causative agents of the changes in the milk may 
at times exist as saprophytes in the cistern (Schultze), or that 
they have at least multiplied in the excretory duct of the cistern. 

Thus Schultze proved that in the appearance of "blue milk" 
the defect can only be removed by a thorough cleaning of the sta- 
ble, animals, milk vessels, and all creamery utensils, and the milk 
-cisterns of the animals must also be treated by antiseptic infusions 
of the udder. 

The "blue milk" is produced by the Bacillus cyanogenes, a Gram-negative, aerobic, 
actively motile, unipolar, flagellated bacillus, with rounded ends, about 0.4/i thick and 
2.4/* long. It is also known as the Bacterium syncyaneum Hueppe (Heim). Growing 
in sour milk the bacillus produces sky-blue to indigo-blue spots which gradually become 
confluent. The bacillus attacks the casein, and produces alkali besides a coloring 
substance, the triphenylrosanilin (Erdmann), which, depending on the reaction of the 
nutritive media, appears greenish or pale blue, violet or indigo-blue, or blackish -brown. 
The Bacillus cyanogenes in itself is colorless. 

The coloring is less typical in sterile milk; a dirty bluish-gray discoloration with 
a reddish hue of the cream occurs, the color gradually diminishing in the deeper parts. 
Indigo-blue spots develop only in sour milk (Heim). 

The changes which occur in milk appear to be especially fre- 
quent in certain localities ; in others they are more rare and appear 
to have a connection with the properties of the soil. Pastures rich 
in clover are supposed to favor the appearance of the defects while 
in woodland pastures they have not been observed, or at least only 
exceptionally. This would explain why the defects occur in cer- 

12 



178 Defects of Milk. 



tain periods during the feeding- of the incriminated feeds, or while 
the cows are feeding in certain pastures. According to observa- 
tions they are observed more frequently in the fall, and during 
wet, foggy weather than during other periods. 

These defects persist tenaciously in creameries and dairies 
and can only be eradicated after a thorough determination of their 
origin. Disinfection of the milk room and utensils with milk of 
lime and hot soda solution, and extending this disinfection to the 
stable in association with cleaning of the animal and possil)ly an- 
tiseptic infusions of the milk cisterns may yield the desired results. 

Another organism causing "blue milk" is the Bacterium cyan- 
eofljioresceus (Zangemeister). It is actively motile, l)ipolar, flag- 
ellated, grows on gchitin in the form of whitish colonies with in- 
dented borders and produces a fluorescent coloring matter in the 
nutritive media. The culture has an odor of trimethylamin and 
putrid fish. The bacteria produce dark blue spots in milk which 
change to a sky-blue color after coagulation of the milk. Other 
blue liacteria are those which occur on hay dust, in water, and in 
sewage in the vicinity of cheese factories, in ditch-water, and also 
the bacteria cultivated by Voges, Claessen, and Beijerinck which 
have been described under the names of B. ccerideum, B. indigan- 
aceum, B. ci/aueofuscum. 

According to the observation of Weigmann and the descrip- 
tion of Hallier certain hyphomycetes may also possess the faculty 
of producing a blue coloration; this is accomplished hj the ac- 
tion of the l)lue coloring matter which they harbor. 

In the zone of the milk supply of Munich ordinary milk de- 
fects occur very rarely; the author observed them in only one 
dairy, and was able to trace the trouble to a certain farm. An- 
other defect of milk occurs much more frequently in the vicinity 
of Munich, the cause of which, according to the author, has not 
yet been described. It concerns the production of brownish milk. 

The bacterium of brown milk appears to be closely related in all its characteristics 
to the proilucer of blue milk; it is 2Afj, lonfj, O.^/jl broad, unipolar, flagellated, actively 
motile, Gram-positive and remarkably resistant to drying. In gelatin it grows especially 
well ai'roliically as a fine, iridescent deposit, which later becomes somewhat thicker, 
turning to a chestnut brown color. The oxygen zone of the lactose gelatin retains a 
saturated brown to deep brownish red discoloration, the nutritive media becoming alkaline 
to litmus. 

A culture of the brown milk organism may be readily produced in milk by rubbing 
traces of the culture of milk having such a defect upon the bottom of a large Petri-dish, 
and pouring over it fresh (not sour) milk. In most instances after 15 to 20 hours 
ocher-colored to sepia-brown spots develop in the cream layer, which enlarge and 
coalesce, conveying to the milk a milk and coffee-like appearance. After coagulation 
the superficial layer of milk again liquefies; whether this is brought on by the bacteria 
of brown milk alone or by peptonizing bacteria which multiply especially well when 
mixed with the bacteria of brown milk, which render the media alkaline, has not yet 
been estaldished. The skimmed milk is not discolored by the JRacilhtft fnftcoficnc-'i. The 
brownish color gradually diminishes from the surface down and at a depth of ^ mm. 
it disappears. 

If the milk is allowed to sour the appearance of gray, orange- 
red, red, yellow, green-fluorescent and violet spots may frequently 



Red Milk. 179 

be observed, which cause a glassy, transparent thickening of the 
wrinkled yellowish-white velvety layer of the oidiimi covering, or 
they penetrate into the depth of the jelly-like layer of the milk. 

Thus under certain conditions the Bacillus violaceus, Bacter- 
ium janthinum, Bacillus lividus, and Bacterium amethystinus, a 
water organism, may appear in violet spots (Schroeder, Zopf, 
Maze, Fliigge and others). 

Greenish-yellow spots and discoloration of the entire sour 
milk are produced by the Bacillus fluorescens which varies greatly 
in its characteristics, at times liquefying gelatin, again only dis- 
coloring it. It is a short rod with motility, but without spore 
formation. 

A red coloring matter is produced by the Bacillus erythro- 
genes Hueppe, which coagulates milk, but liquefies it later through 
peptonization, coloring the whey red. 

According to Gruber a flagellated short rod, the Bacillus lac- 
toruhefaciens is supposed to produce a slimy condition of milk 
with the formation of a red coloring matter. Other bacteria such 
as the Micrococcus cerasimim (Keferstein), the Sarcina rosea, the 
Bacillus prodigiosus and others, form red spots. Red varieties 
of yeasts have also been found. 

The author demonstrated through the examination of a dirty 
and dry milk pail that the layers of color which adhered to dif- 
ferent parts somewhat like red varnish consisted of blue-red yeasts 
which had grown on the dried milk residue. The accumulation of 
color was present in the yeast cells proper, which on examination 
showed a reddish transparency. Their attempted cultivation was 
unsuccessful. 

The discolorations of milk may vary from red, and pink, to 
rust-color and orange. 

Yellow coloration sometimes only of the cream, at other times 
of the entire milk is caused by the Bacillus synxanthus (Schroter), 
the Sarcina lutea, the Sarcina flava, and Bacterium fidvum and 
others. Wild yeasts and moulds, which have been observed by the 
author may also cause a yellow coloration of sour milk. The 
Bacillus ■fluorescens, may at times cause a yellowish-green 
discoloration. 

Other bacteria again show the action of their vegetation by 
the development of a tenacious slimy consistency of the milk. 
Strains and varieties of the peptonizing bacteria in which acid for- 
mation is dissipated and the peptonizing action of which retracts 
against the properties of producing rennet-like substances, may in 
a few hours cause a casein coagulation, and thereby convey to the 
milk a granular consistence. This defect is relatively rare, and on 
the contrary the milk may become non-coagulable, slimy and bitter. 

More frequently, especially by keeping the milk in a warm 
place, a change of the milk to a slimy consistence may be observed. 
The action of the slime-forming bacteria may appear in two forms. 



180 Defects of Milk. 



and render slimy either the entire inilk, or the casein is precipitat- 
ed and only the whey develops a strong- tenacious, stringy 
consistency. 

The canse of the slimy condition may l)e produced either by 
a slimy change of the sugar, M'hieh is accomplished with the form- 
ation of a high molecular weight body, the galactan or the viscose, 
or by the swelling of the bacterial capsules which form a mucin- 
like substance. 

The best known producer of slimy or stringy milk is the Strep- 
tococcus lioUandicus, the cause of the "long whey," which is con- 
sidered by Weigmann as a degenerated streptococcus of lactic acid 
fermentation. If cultivation of the producer of the "long whey" 
is continued at 35 deg. C. it loses the property of producing slime, 
and changes into a lactic acid producer. 

From various groups of bacteria the following have been 
proved to be slime producers: Bacterium lact'is loyigi — a strep- 
tococcus — in Swedish thick milk (Troili Petersson), Micrococcus 
(streptococcus) viscosus (Schmidt-Miihlheim), Micrococcus my- 
cilaginosus from slimy cream (Eatz), and Streptococcus hurri 
from stringy whey. 

Slime is further known to be produced by the colon-aerogenes 
group (Emmerling, Schardinger), the Bacillus guiUeheau, as well 
as the Bacillus lactoruhefaciens. Adametz, Duclaux, Gruber, 
Ward, Eckles, and Marshall have also isolated slime producers 
from milk, whey, food substances, straw, stable air, and spring 
water. 

Other defects of milk which are associated with change of 
consistency (and color changes), are produced by milk drawn from 
affected udders, w4iich subject has been discussed in the section 
on "Diseases of the Udder." 

Considering the living requirements of the special varieties of 
bacteria, the defects of milk appear to be especially frequent under 
certain weather conditions and in certain periods of the year. 
Thus the milk dealers of Munich complained of the appearance of 
defects of taste, especially in the cool and cold period of the year, 
and at the time of changing the animals from stable to pasture 
feeding and vice versa. The cause may lie in the fact that with the 
beginning of the dry, that is stable feeding, the microbian flora of 
the intestinal canal and of the forage and the stable air is different 
from that existing during the period of pasture feeding, and 
thereby other species of bacteria, aroma producers, contaminate 
the milk; likewise in certain cold climates and in certain methods 
of keeping milk the bacteria, excepting the lactic acid producers, 
find just the requirements which aid them in their propagation. 

In 1909, the following defects of milk were found among 1,000 
samples examined monthly: 



CQ 



c: 



^ 



lO 



^ 



CO, 



CQ 



Various Defects. 






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GfO' 



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-* 



to 

CO 
CD 



CM 

id 



o 



o 

CO 
C30 



oi 



C30 

p 

CO 
CD 
CM 



CD 



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-* 



CD 



CD 
CX) 



cc 

CO 



oo 

CD 



CD 
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CO c^ 



CD 



CD 



cm" 



CD 






CM 



CO 
CO 



iQ 
-* 
CD 



CD 



o 
o 

CM 



CO 



CO 



CM_ 

CD 
CD 
CO 



o 



CD 



^ Oi 



lO 



lO 



lO 



ai 

CM 



p 
CM* 
CM 



O 
'^ 

oi 
CM 



cji 
GO 
CM 



lO 



CO 
CM 

CO 



CM 



CO 
CD 



go' oo 



cri 



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GO 



CM 

CD 



>. 



o 



Cd r^ 



iq 



181 



IX) 
t^ 



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in 

CD 



CD 



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o 



CD 
CM 



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GO 
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(M 

O 



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irt) 

CD 



CD 
CO 



O 

o 

CO 
CM 



P 

CO 
CD 
CO 



(M 

O 
<M 



CO 



uo 

CO 



lO 

CO 



oo 



!>. 



bfj 



;:3 
be 

o 
o 



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CO 
CM 



CM 
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<D CO 

I>^ GO 

GO 



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vd 
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Qa2a2P^QPHOpqOc/2a2PHpQ 



182 Defects of Milk. 



At the same time it appears as though the spoiling- of milk, 
for instance by souring, is less inHnenced by the temperature, 
Avhieh of course may be of importance, than by the atmospheric 
pressure. It could hardly be attributed to an accident that, ex- 
cept at harvest time when the milking is sometimes hurriedly done, 
the number of samples spoiled by souring were almost in recipro- 
cal relation to the measured average value of the atmospherici 
pressure for the month. 

Likewise in several months a certain parallel exists between 
the occurrence of dirty milk and souring, so that the dirt is present 
in largest amounts during August, September, October and 
Novem])er. 

Months in which milk contains a great deal of dirt appear 
also to favor the requirements for the development of a putrid 
taste. (Height in June, August and October, harvest time.) Dur- 
ing this period the milk is not aired and cooled, so it "suffocates." 
The cans are not cleaned, and all dairy work is slighted. 

Direct contamination with cow nianine appears to be of less importance in the 
development of an animal llavor, than polhition with bacteria from the skin of the 
cow, which may contaminate the animal while in pasture. These views are strongly 
siipi)orteil by the experiments of Wolf and Weigniann, who proved the identity of the 
bacterial ilora of the defective milk with the bacteria which were cultivated from the 
]iastiire plants, and by the experiments in which the authors succeeded in reproducing 
artificially these defects by nsing special bacteria. 

This view is also supported by the observations of the author. A milk dealer 
complained about the bad taste of milk in a certain delivery. It was noticed that only 
the evening milk of the farm, and not the morning milk possessed the defect. Before 
the evening milking the animals were kept in a pasture during the day. It was remarked 
from the beginning that the morning milk did not have the taste, which was the more 
suprising since the animals by standing in the stable during the night must have affected 
the purity of the stable air. Nevertheless the evening milk which was obtained in the 
stable after a sufficient airing and cleaning, possessed the objectionable taste. Of course 
the time could have played a part since both the morning and evening milk were delivered 
at the same time, the evening milk being allowed to stand all niaht at a temperature of 
12 deg. C. The milk was kept in a milk room next to the stable. 

The conditions, however, were not changed by removing the milk immediately after 
milking, to a well-ventilated room, cooled by ice. 

The passing of the odoriferous substances into the milk directly from the food 
could be excluded since the substances could then have been demonstrated in the morning 
milk as well, and therefore the only explanation which remained was that while lying 
down the abdomens of the animals became contaminated with the bacteria of pasture 
plants (meadow grass and clover). These bacteria contaminated the evening milk during 
milking in the stable, whereas the morning milk was principally contaminated with 
bacteria from the bedding. All other factors could be given about equal consideration. 
That the age of the milk did not play a part was proven by the fact that the morning milk 
in spite of longer keeping during both cold and warm weather in exposed or covered 
vessels, had never been affected by the disagreeable taste. 

It is almost impossible at the present time to establish definite 
relations between defects in milk and contamination of milk with 
bacteria, since the propagation of the bacteria causing the defects 
may be influenced by the most varied factors. 

It should be especially emphasized that bacteria of one and 
the same species may under certain conditions produce different 
defects in milk, depending on the accompanying conditions, as for 
instance whether they are associated with one or several other 
species of bacteria. 



Coagulation Types. 183 



According to Wolff and Weigmann the Bacterium fluorescens 
possesses the characteristic of producing by itself an ester-like 
odor, while together with the Bacterium mycoides and the Strep- 
tococcus lacticus it produces a disagreeable aroma, and finally 
with the Bacterium megatherium, B. mycoides, and lactic acid 
bacilli it produces a cheesy odor. This of course renders the study 
of milk defects difficult, since a bacterium cultivated in pure culture 
may show an entirey different action than when present in milk in 
a mixed culture, and mixed culture experiments with the entire 
flora would become necessary. 

Types of Coagulation. 

The decomposition and fermentation microorganisms, which 
develop in milk, are utilized in the examination of milk that is in- 
tended for the manufacture of cheese. A fermentation test is 
made from each delivery of milk, and after a certain time each 
sample is tested for odor, taste, and in regard to its appearance 
and visible changes. 

According to Jensen the fermentation may be distinguished as : 

1. A fluid type, 

2. A jelly type, 

3. A gaseous type, 

4. A whey type, 

5. A cheesy type. 

It should be emphasized that milk samples rich in bacteria 
usually produce a good jellylike type, whereas in milk samples 
containing few bacteria, whey fermentation frequently occurs. 

The jelly type results in the profuse presence of lactic acid 
formers, which distend and tear the coagulum by the action of 
aerogenes varieties and cheese bacteria, whose gas production fre- 
quently forces the coagulum upwards. The milk becomes whey 
when true saccharomyces varieties form gas at the moment of 
coagulation. At the same time sub-types may be distinguished, 
such as porous, granular and flaky. The cheesy fermentation 
type develops in the presence of an increased number of rennet- 
producing bacteria. 

These fermentation tests of milk are important to ascertain if 
it is in satisfactory condition for cheese production. For the de- 
termination of its fitness for drinking purposes, however, these 
tests are of little importance, since the questions relative to the 
value which these bacteria possess in the nutrition of man, have 
never been satisfactorily answered. 

Bacterial Reductase, Bacterial Catalase and Lactic Acid 

Production. 

Among the characteristics of milk bacteria, which are of 
especial interest are those which are utilized in the examination 
of milk, and which may have a disturbing effect in experiments 



184 Reductase, Catalase, Etc. 



eondncted for tlie demonstration of ori,i^-inal ferments because of 
the reactions wliicli they cause. One characteristic is the reduc- 
ing property of some bacteria and their ability to split up HX).. 
into water and molecular oxygen, corresponding to the action' of 
catalase. 

The reducing action of bacteria as indicate.] bv the presence of re.hu-tase lias 
been observed for a long time. Heln.holtz in 1843 proved that putrefactive changes 
nhu-h conhl not be demonstrated by changes of odor could be proved by discoloration 
ot litmus coloring matter. Subsequently this reducing action was confirmed by many 
authors .0 be t lie property of various anaerobic and aerobic organisms. Thus according 
to Gayon and Dupetit the anaerobes are capable of forming ammonia from nitrates 
while the Bacillus produ/io.sius, B. anthracis, Spir. finkler and Staph, ilocuccns citreus 
torm nitrites out of nitrates. Others again reduce sulphur to H.S (through "Hvdro- 
genase ). " ^ -^ 

As an agent for demonstrating the reductase processes some authors, for instance 
^plna, Cahen and Wolff, use coloring substances which change into leuco-compounds, 
as a result of the reduction, but from renewed contact with the air they become re- 
oxydized, as for instance tincture of litmus, thionin, methylene blue, indigo" blue, neutral 
red, etc. Others again iise metallic salts to render the reduction directly visible (Scheur- 
len and Jvlett, Gosio), for instance selenite and tellurite, whose sodium and potassium 
compounds confer upon the colonies a brick-red or grayish-black tinge, by the reduction 
or indirectly, the transpiring reductive action is shown through secondary reactions for 
instance the formation of nitrites from nitrates, through the addition of iodine starch 
paste which becomes decolorized by the nitric acid. 

Methylene blue is used at the present time most extensively 
for the reductase test; that is, the solution recommended bv 
Schardinger consisting of 5 parts of concentrated alcoholic methy- 
lene blue solution to 195 parts of water is best adapted for the 
examination of milk. 

The reducing qualities of various bacteria towards methylene 
blue vary. Thus Jensen established the reduction qualities" of a 
series of milk bacteria, and proved that varieties of colon, staphy- 
lococci, sarcina, and mould fungi, reduce rapidly, whereas acid 
streptococci do not decolorize the solution. 

The findings of Koning, who used cultures 24 hours old in his experiments, were 
the same. Arranged according to length of time, reductions take place as follows: 

Bacillus fiuorescens nonliquefaciens, in g min 

Bac. acidi lacUci Hueppe, in \\ jo ^:^^ 

Bac. prodigiosus, in 10-15 min' 

Bac. piorescens liquefaciens, in 13 n,jjj' 

Proteus ,opfii, in. :'.::: .::::['.: 15 min! 

Bac. coll communis, m 27 j^-|- 

Bac. subtilis, in on ^iJ 

■nf , . ' . oO mm. 

Mesentericus, m «a ^• 

ilk bacteria I, m on Tn,-,, 

r,i , . r, \ . .-, ou mm. 

btreptococci of lactic acid, Oidium lactis and 2 stable atmospheric 

bacteria, not in 90 j^^j^, 

Schardinger in 1902 stated that suspensions of the Bacillus acidi laevolactici 
decolorize m 3 minutes, the Bacillus pa-soformans in 3 minutes, the Bacillus lactis 
pituitosi m 80 minutes, the Bacillus coli in 1.5 to 20 minutes, etc. 

The ability to reduce methylene blue has also been found in anthrax and tubercle 
bacilli. 

In the experiments it was proved that although not all bacteria are capable of 
reducing methylene blue, the power of reduction in some is very strong, while in o^^hers 
it IS diminished and in still others it is practically nil. 

Reduction properties appear to be characteristic of the living 



Reducing Properties of Milk. 185 



bacterial cell, which do not pass into the filtered fluid (Schar- 
dinger, Spina, Cahen). 

From the above mentioned facts it is evident that milk which 
contains numerous bacteria has a strong reducing property. 
Through the works of Smidt, Mtiller, and Schardinger it has been 
proved that as a rule the richer the milk is in bacteria the earlier 
the reduction of the aqueous methylene blue solution at 37 deg. 
will occur. Milk drawn under sterile conditions fails to reduce the 
methylene blue solution even after days (Rullmann). Miiller 
proved that freshly drawn and cleanly handled market milk re- 
quires 10, 12 or more hours for reduction (mixing 10 parts to 1 part 
of methylene blue solution), whereas fresh market milk during 
cold weather requires 6 to 9, and in warm weather only 1 to 2 hours 
for the decolorization. At the stage when bacteria begin to multi- 
ply, which is at the end of the incubation period, the time required 
for reduction amounts to from 1 to 2 hours. If sour milk or cow 
manure was added to fresh milk the time of reduction was 
hastened. 

He therefore proved that all factors which favorably influence 
bacterial growth hasten the reduction. 

In the author's first investigation he found that 10 e. c. of milk with about 44,000 
bacteria per c. e. failed to reduce one c. c. of methylene blue solution in six hours. 

With about 200,000 bacteria reduction took place in 4 to 6 hrs. 

With about 500,000 bacteria reduction took place in 3.5 hrs. 

With about 1,600,000 bacteria reduction took place in 2 hrs. 

With about 6,000,000 bacteria reduction took place in. 70 min. 

With about 350,000,000 bacteria reduction took place in 50 min. 

With about 800,000,000 bacteria reduction took place in 15 min. 

Similar results were obtained by Jensen as follows: 

With about 264,000,000 bacteria reduction took place in 1 min. 

With about 80,000,000 bacteria reduction took place in 3 to 5 min. 

With about 50,000,000 bacteria reduction took place in 10 min. 

With about 7,000,000 to 11,000,000 bacteria reduction took place in 40 to 60 min. 

With about 3,000,000 bacteria reduction took place in 2% hrs. 

With about 1,600,000 bacteria reduction took place in .... 7% hrs. 

With about 1,000,000 bacteria reduction took place in 6% hrs. 

With about 126,000 bacteria reduction took place in 91/^ hrs. 

_ Since the degree of acidity increases with the growth of bac- 
teria there exists a certain connection between the degree of acidity 
of the milk and the rapidity of reduction, and since the degree of 
acidity increases rapidly after incubation, a rapid reduction would 
be expected to follow a rapid increase in the degree of acidity. 

This is also proved by Jensen 's experiments. Milk which reduced in one minute 
had after 12 hours, at 25 deg. C, a degree of acidity of 36. 
Milk which reduced in — 

5 min. after 12 hrs. at 25 deg. had an acidity of 19 

8 min. after 12 hrs. at 25 deg. had an acidity of 20 

6 min. after 12 hrs. at 25 deg. had an acidity of 35 

10 min. after 12 hrs. at 25 deg. had an acidity of 22 

8 min. after 12 hrs. at 25 deg. had an acidity of 18 

7 min. after 12 hrs. at 25 deg. had an acidity of 28 

1 hr. after 12 hrs. at 25 deg. had an acidity of 15 

% hr. after 12 hrs. at 25 deg. had an acidity of 25.5 

1% hr. after 12 hrs. at 25 deg. had an acidity of 11.5 



186 Reductase, Catalase, Etc. 



21/4 hr. after 12 hrs. at 25 deg had an aeidity of 15 

S'-Yi hr. after 12 hrs. at 25 de^r. had an acidity of 9 

6Vi hr. after 12 hrs. at 25 deg. had an acidity of 9 

7 hr. after 12 hrs. at 25 deg'. had an acidity of 10.5 

Gl-t hr. after 12 hrs. at 25 dej^'. had an acidity of S 

7^2 hr. after 12 hrs. at 25 deji'. had an acidity of 8 

12i/i hr. after 12 hrs. at 25 dco-. had an acidity of 7 

S\-2 hr. after 12 hrs. at 25 deg. had an acidity of 7.5 

The findings of the anthor were very ninch the same as those of Jensen. 
]\rilk Avhicli failed to reduce in 20 hours had after 24 hours at 20 deg., from 7.4 to 
10 degrees of acidity. 

The following- table shows the results of the technique em- 
ployed in testing- milk, where the reduction number is understood 
to mean the number of drops of methylene blue solution which in 
a given time was completely reduced by 5 c. c. of milk: 

Degree of acidity After 24 hrs. Time required 

at delivery at 20 deg. for reduction Eeduetion number 

7.0 7.4 20 hrs. 

6.2 8.6 20 hrs. 

6 10 20 hrs. 

6 9 20 hrs. 4 

7 10 20 hrs. 
6 24 4 hrs. 2 

6.4 26.5 8 hrs. 10 

6.5 20 8 hrs. 6 
6.2 24 8 hrs. 8 
6.2 27 8 hrs. 6 
6.8 23 8 hrs. 4 
6 14 8 hrs. 4 
7.8 30 6 hrs, 4 
6.5 28 2 hrs. 2 
7.2. 32 Ihr. 2 
6 34 Ihr. 2 
6.2 38 Ihr. 10 

8 40 5 hrs. 10 
10.5 26.4 0.5 hrs. 10 

6 30 6 hrs. 2 

These numbers were obtained from a great number of sam- 
ples during work at the milk control station, without any selec- 
tion. They show that milk which sours rapidly, and is therefore 
at the end of the incubation period, also reduces rapidly; there 
exists, however, no absolute constancy in the parallelism, neither 
with the values of acidity in milk after twelve to twenty-four 
hours, nor with the values in samples of fresh milk. 

After thorough souring the reduction power of the milk again 
diminishes for a time. This may be due to the fact that the acid 
reaction inhilnts the reduction power — as a matter of fact the 
rapidity of reduction is again considerably increased by the addi- 
tion of sodium carbonate or bicarbonate — and also because a non- 
reducing organism, the acid streptococcus, outgrows the other 
bacteria. 

The addition of an alkaline solution brings about acceleration 
of the reaction only in sour milk, while in milk with low bacterial 
count the reaction is retarded, but this may be overcome when 
through acid formation neutralization has taken place. 



Bacterial Catalase. 187 



Antiseptics, such as boracic acid, salicylic acid and formalde- 
hyde, inhibit or destroy the reduction power of bacteria; the 
same result is obtained by heating, which destroys the life of 
the vegetating bacterial cells. 

Milk which has been heated for 10 to 30 minutes at 80 to 100 
deg. C. shows only the slightest reduction power, _which_ increases 
again only after the recurrence of bacterial multiplication. 

It should be emphasized that milk, in spite of being spoiled 
to a marked degree, may have a slow reducing power, as for 
instance soapy nnlk, provided this condition is not associated with 
extensive bacterial contamination with other species of bacteria. 
Although the bacillus of soapy milk reduces very rapidly, soapy 
milk in itself is only capable of bringing on this reaction to a 
very slight degree, which probably is proof that defective flavors 
may result even when only a very slight bacterial growth has 
taken place, although the bacterial action is of tremendous 
importance. 

For the completeness of this chapter it should be mentioned 
that milk very rich in bacteria, which has been sterilized by heat, 
reduces also the formalin methylene blue solution as a result of 
the original bodies in milk, a property which has nothing to do 
with the Schardinger reaction. 

The formalin methylene blue reducing principle in market 
milk is also a pre-formed substance, which occurs in milk drawn 
under sterile conditions (original ferments). 

Bacterial Catalase. 

Similar to the power possessed by body cells and body juices, 
bacteria have the ability of splitting gaseous oxygen from hydrogen 
peroxide solutions. This property may be observed in many bac- 
teria, but it should be mentioned that not all species of bacteria 
possess it, and that certain bacteria have a specific power in this 
direction. 

Koning and Jensen made confirmatory statements to this 
effect, having found that the acid streptococci of milk do not split 
H2O2. The author's experiments confirm this observation. Jensen 
made an especially interesting observation, namely ,_ that the bac- 
terial flora present in milk during the incubation period of souring 
usually possess strong catalytic properties. 

The following data are taken from a work of Koning, arranged according to the 
catalase figures : 
Species of Bacteria Catalase test Reductase test 

B. prodigiosus ^^ ^'^ minutes 

B. proteus eopfii 57 15 minutes 

Milk bacterium 1 55 80 minutes 

B. fluorescens liquefaciens 53 13 minutes 

B. eoli communis 39 17 minutes 

B. lad. acid. Hueppe 32 12 minutes 

Stable air bacteria II 31 90 minutes 

B. meseniericus 30 60 minutes 

B. flxiorescens nonliquef. 29 15 minutes 



188 Reductase; Catalase, Etc. 



Stable air bacteria T 28 90 minutes 

B. suhtilis 17 40 minutes 

Milk bacteria IJ 15 90 minutes 

B. miicoidcs 11 90 minutes 

Oidiurn lacU.^ 11 90 minutes 

Sir. mastitis lungus 90 minutes 

From those figures it may be seen that frequently with a high 
catalase number a very rapid reduction time may be present. 

Jensen found similar conditions in his investigations; he, 
however, expresses himself as believing that a parallelism of 
))oth factors does not prevail. Arranged according to catalase 
values expressed in figures, giving the number of c. c.'s of oxygen 
formed, the relation between catalase and the time of reduction is 

as follows: Catalase Eeductase 

B. protexis vulgaris 27 c. e. 7 minutes 

B. protetis zopfii 27 e. c. 5 minutes 

B. prodigiosus 27 c. e. 7 minutes 

Microc candic 27 c. c. 4 minutes 

Microc. A 27 c. c. 3 minutes 

B. coli 18 e. e. 5 minutes 

B. aerogenes 9 e. c. 10 minutes 

B. mycnides 7 c. e. 12 minutes 

B. dentrificans 1 C. C. 10 minutes 

With other bacteria, for instance, butyric acid bacteria, there 
appears to be no relation between the reduction power and the 
development of oxygen, whereas with certain lactic acid producers, 
for instance, the streptococci and cheese bacilli, the inability to 
develop oxygen coincides with the long time required for reduction. 

In unspoiled milk during the incubation stage of souring and 
at the beginning of souring at the end of this incubation stage, the 
bacterial catalase will always have to be considered, but in general 
the bacterial action in slowly reducing milk is very slight. If in 
the latter instance high catalase values are obtained then usually 
the catalase originally present in the milk is responsible for it. 

Koning further showed that catalase increases with the age of milk, and with a 
rapid angle of incidence. The line of incidence in fresh milk is at first only 
slightly bent, later more or less so, whereas old milk uniformly shows a rising line. 
Spindler's recent experiments confirm this statement. From the investigations of 
Spindler, however, it may be observed that during the time when milk is fresh enough 
for drinking purposes the fluctuations are only very slight and the catala?e value 
obtained is always greatly dependent on the original catalase value of freshly drawn 
milk. Faitelowitz indicates that catalase multiplies many fold after keeping fresh milk 
at room temperature for 24 to 30 hours. 

Through heating to 70 deg. C. the ''bacterial catalase" is 
destroyed, or at least the bacteria are attenuated in their action to 
such an extent that the oxygen-splitting property becomes almost 
nil. Chick has already ascertained that this inactivation of the 
bacterial catalase may be abrogated in a certain time by inoculation 
of the heated milk with raw milk and Koning states that old 
pasteurized milk, or milk freshly pasteurized with insufficient heat, 
splits the H2O2. The catalase test is therefore recommended by 
Kniisel for the examination of pasteurized milk as to its suitability 
for drinking purposes. 



Acidity of Milk. H 



It is to be regretted that the bacterial catalase cannot be 
separated from the original catalase, so that it would be possible 
to draw definite conclusions from the catalase findings of market 
milk, as to whether the catalase quantities which are demonstrated 
were present in the freshly drawn milk or whether they have been 
subsequently formed by bacterial growth. Wolf claims that milk 
Avhich reduces slowly and shows a strong catalytic property by 
the formation of large quantities of oxygen should be suspected 
of containing secretions from animals with affected udders. It 
would be impossible to draw conclusions based on this statement 
in those cases where rapid reduction occurs coincidently with 
strong catalytic action. 

Degree of Acidity. 

In discussing the original properties of milk it was mentioned 
that casein, acid salts of milk, carbonic acid, etc., give to milk an 
acid reaction to phenolphthalein. 

Even immediately after milking, in order to produce neutral- 
ization of the milk against phenolphthalein, several c. c. of sodium 
hydrate are required. The number of cubic centimeters of a 
normal Na OH dilution which are needed to neutralize a certain 
quantity of milk are known as degrees of acidity. The number 
obtained varies, depending on the method and dilution employed. 

Thus Soxhlet-Henkel, for instance, employed 100 c. e. of milk 
and 14 normal Na OH and obtained an average value of about 
6 to 7 degrees of acidity, 

Jensen, who works with tV normal Na OH, uses on an 
average 18 to 19 c. c. 

Thorner dilutes 10 c. c. of milk with 30 c. c. of water and 
titrates with to normal Na OH. 

The degrees of acidity, as determined by Dornic, are higher 
than those of Soxhlet-Henkel : He uses 10 c. c. of milk and alkali 
which contains 4.445 gm. Na OH to 1000 H^O. tV c. e. of alkali, 
according to Dornic, is equal to a degree of acidity. 

Schrott-Fichtl and Dornic suggested as an advantage the drop- 
ping of the ''scale of degree of acidity" and employing an alkali, 
1 c, c. of which would correspond to 0.01 gm. of lactic acid, or to 
figure the degree of acidit}^ on the basis of lactic acid. Then 
1 c. c. of TO alkali would correspond to 0.009 gm. of lactic acid 
and 1 c. c. of 14 normal Na OH=22.5 gm. 

Of course, it should be remembered that the neutralization 
of the alkali does not correspond entirely to the amount of lactic 
acid present but depends also on other factors, for instance, on 
the proportion of acid phosphates, carbonic acid and casein. 

Only the increase in acidity which is obtained by a compara- 
tive testing of fresh milk and an older sample of the same milk, 
should therefore be considered as lactic acid, since Henkel proved 
that free lactic acid is not present in freshly drawn milk. 



190 Reductase, Catalase, Etc. 

The degree of acidity of milk depends on the lactation period. 
Colostrum, milk of animals with affected ndders, and milk from 
freshlj'- milking- cows have an abnormally high acidity, while milk 
from animals in the last stages of lactation, and sometimes milk 
from affected ndders, may be lower than normal. 

Besides these factors the degree of acidity of milk is also 
influenced by the growth of bacteria, the species of bacteria, and 
therefore by all factors which have an influence on the bacterial 
gi'owth, such as cleanliness in milking, cooling, outside tempera- 
ture, age of the milk, etc. 

Plant, for instance, demonstrated that milk ^vhir-li has been kept — 

At a ti'iiiperaturo of showe<l multiplication of ami voluntarily coagulated 

liaeteria after after 

lOdefT. C. 48to72hrs. 100 hrs. 

l-> <leff. C. 20 to 24 hrs. 63 hrs. 

20 deg;. C. 12 to 20 hrs. 48 hrs. 

2-"> deo:. C. 8 hrs. 24 hrs. 

."hides'. C. 7 hrs. 22 hrs. 

37 deg. C. 5 hrs. 12 hrs. 

Koning- has also kept milk at various temperatures and titrated the degree of acidity 
after varying peiiods: 

Kept at 7 to 9 deg. L\ Kept at 22 deg. C 
Deg. of aciditv Deg. of acidity 

withi/ioNaOH 

Milk after delivery. . 13.6 13.6 

After 15 hours . . ' 14.6 14.6 

After 29 hours , 14.6 20.6 

After 41 hours 16.0 62.6 

After .53 hours 16.0 71.0 

After 65 hours 16.8 

After 77 hours 17.6 

After 89 hours 18.8 

Since the growth of various bacteria depends on the method 
of keeping the milk, therefore the acid formation varies in accord- 
ance with the same conditions during the same time. Koning's 
experiments confirm these findings : 

Time of Milk in shallow vessels Tn tall cvlinders 

delivery at 22 deg. at 37 deg. C. at 22 deg. ' at 37 deg. C. 

Shortlv after milking. 18.6 

After 24 hours 16.4 18.5 18.8 32.4 

The degree of acidity depends, furthermore, upon whether 
fresh milk is boiled or raw; in boiled milk it is lower than in raw 
milk, and it also depends on the aeration of the milk. 

Milk drawn carefully into bottles 25 minutes after the milk- 
ing has 17.4; after being aired by pouring from a height of 
V^ meter, 16.4; after repeated aeration 16.1, and after boiling- 
only 16 degrees of acidity (Koning). The escape of the volatile 
carbonic acid seems to play a part in this. 

Finally, the degree of acidity depends on the method by wdiicli 
it is tested. For instance, if the milk is diluted with water for 
the purpose of titration (method of Thorner, Pfeifer, etc.), then 
through this addition of water, a solution of alkaline calcium 
phosphate takes place and the acidity becomes less. 



Typhoid Fever from Milk. ^91 



Since the acidity varies immediately after milking, after lac- 
tation, among individuals, and even in milk from different teats, 
and from interrupted milkings, the immediate measuring of the 
degree of acidity constitutes no proof of the age of the milk. The 
periodically continued titration of the same sample may, however, 
be a good indication as to whether the milk has passed the incu- 
bation phase and thereby afford an approximate indication of 
the ''age.'' By "age" is not understood the difference in time 
between milking and examination, but a condition which may ap- 
pear in milk sooner or later, depending on the cleanliness in its 
preparation and handling, and on the outside temperature. This 
condition is effectively determined by the reduction of meth3dene 
blue. ^ If the milk has once passed the incubation time the curve 
of acidity rapidly and progressively rises, when the milk is kept 
subsequently at temperatures at which lactic acid bacilli grow pro- 
lifically (20 to 37 deg.). 

Koning made a test of milk which at deliverv gave a degree 
of acidity of 15.8 (xV n Na OH :100), ' ^ 

And showed after at 10 deg. 22 deg. 37 deg. C 

1 day 16.4 28.8 96.0 

2 days 16.7 91.1 92.8 

3 days 17.2 102.4 105.2 

4 days 17.9 96.4 144.0 

5 days 26.2 105.6 184.0 

6 days 39.2 103.2 219.6 

7 days 57.6 102.8 241.6 

8 days 65.2 106.0 261.6 

Since, however, the amount of lactic acid formation does not 
depend on the time and temperature alone, but also on the variety 
of bacteria growing in the milk, only general conclusions as to 
the aging of the milk can be drawn. 

Subsequent Contamination With Infections of Man. 

The occurrence of disease producing agents in milk is of 
interest from the standpoint of tracing the origin of disease, 
but from a milk inspection standpoint it "is a most thankless field. 
These disease producers may originate from affected persons, or 
from healthy bacilli carriers, or they may reach the milk through 
infected material, as, for instance, infected water used in washing 
utensils, or as an adulterant, or in the treatment and preparation 
of milk products. 

That milk may become a transmitter of disease has been posi- 
tively proven. 

1. ^ Typhoid Fever. The causative agent may contaminate 
the milk tlirough infected water, through vessels which were 
returned without cleaning from houses harboring persons affected 
with typhoid, through affected and convalescing patients who' are 
employed in producing or in the subsequent handling of milk, and 



192 Infections ■ of Man from Alilk. 



tlirougli attendants and other intermediate hosts, especially 
throngh bacilli carriers. Konradi positively demonstrated typhoid 
l)acilli in such milk. Levy and Jakobstal discovered true typhoid 
bacilli in an abscess of a cow so that under certain conditions it 
should l)e considered possil)le for typhoid bacilli to gain entrance 
into the milk directly from the udder of the cow. 

2. Paratyphoid Fever. All that applies to typhoid bacilli 
holds equally true for paratyphoid, and to other bacteria of that 
type, for instance the Bacillus enteritidis and the Bacillus paracoli. 

In these affections especial attention should be directed to 
the animals which are affected with intestinal inflammations, 
purulent metritis, and acute, severe inflammations of the udder, 
and also to stables in which white scours of calves and calf-ill 
occur frequently. 

The possibility of the transmission of scours to man has been 
indicated by Lenz, Jelile and Charleton. Up to the present time, 
however, its certain transmissibility through milk has not been 
satisfactorily demonstrated. 

3. Cholera. 

4. Diphtheria, 

5. Tuberculosis, Rabinowitsch demonstrated tubercle bacilli 
of human type in milk. 

6. Scarlet Fever. 

The sanitary police or the authorities in charge of milk con- 
trol in all cases in which a suspicion prevails that such diseases 
have been transmitted through milk can provide that the possi- 
bility of the continued spread of such infections should be pre- 
vented. The sanitary police authorities should continuously im- 
press upon all persons interested in the production of milk, and 
in the dairy industry, that there are always possibilities of the 
transmission of disease ; and the attendant physicians should cau- 
tion the patients and their families as to the danger of allowing 
it to spread further, and any violations should be dealt with to 
the extent of the law. 

The health authorities of a locality at every appearance of a 
dangerous epidemic should consider the possibility of the develop- 
ment of the disease through milk consumption, and should trace 
the places from which the affected persons and their families 
draw their milk supply". If from these investigations there exists 
the slightest cause to assume that the milk supply may be the 
original cause, the attending physicians should cause a further 
investigation of the matter. In the meantime the suspected milk 
should be rendered harmless by pasteurization. 

With these remarks an intrusion has been made into the 
chapter upon *Hhe supervision of the milk traffic and milk control," 
which will be given special consideration. 



Destruction of Bacteria by Heat. 



The Destruction of Bacteria in Milk. 

it ' ' JTir purpose to discuss briefly the destruction of bacteria 
in milk, which aims to free the milk from disease-producing germs 
and add to the keeping quality of the milk. 

In practice this is accomplished most frequently by heating, 
in which the following distinctions are made : 

1. Sterilization of the milk ; 

2. Simple boiling ; 

3. Pasteurization. 

If it is desired to judge the value of these methods of prepa- 
ration, the question first considered must be, what changes does 
the milk undergo through heating! Milk is a biological product 
the properties of which may be considerably influenced by cold 
and heat. 

It is generally known that after heating milk retains a so- 
called boiled-milk taste, and that this becomes stronger the longer 
the milk is subjected to a temperature of from 70 to 100 deg. C. 

The method of heating is important for the appearance of the cooked taste. 
Open boiling even for a short time produces a marked change in taste when compared 
with heating in specially closed utensils or in bottles after subsequent cooling. 

The curdling of boiled milk is more difficult than with raw 
milk ; the boiled milk in curdling after a long time forms a loose, 
coagulum with less uniform consistency. This change is not so 
pronounced with heating between 70 to 80 deg. as in boihng and 
in heating to over 100 deg. C. 

Depending on the height of the temperature and on the length 
of time the heat is applied, globulin (at 75 deg.) and albumin (at 
80 deg.) are precipitated. Proteids which are precipitated m milk 
by heating to boiling temperature disappear if the boiling is con- 
tinued. According to Peiper and Eichloff the intermolecular at- 
tachments of the proteids become loosened by heating to high 
temperatures, and leucin, tyrosin, ammonia, sulphureted hydrogen 
and phosphorated hydrogen are formed. If the heating has been 
conducted in poor earthenware or glass vessels, especially new 
ones, potassium silicate will pass into the milk. Fynn noted the 
absence of sulphureted hydrogen from heated colostral milk. The 
reaction became apparent only on the fourth day of lactation. The 
formation of sulphureted hydrogen and phosphoric acid in milk 
results from the splitting up of casein. 

Hydrogen sulphide can be demonstrated in canned milk even months after heating, 
whereas in sterile bottled milk, under the influencee of light and m the presence ot 
oxygen, the sulphide of hydrogen is utilized for the formation of water and sulphur. 

In higher heating the milk becomes brownish through caramel- 
ization of the milk sugar and the lecithin content of the milk 

13 



194 Effect of Heat. 



diminishes, wliicli, according to Kida, may be seen from the fol- 
lowing- example : 

In 1000 c. e. of milk, lecithin was present as follows : 
Unheated samples... 0.474 gm. 0.474 0.505 0.467 0.462 0.517 

Heated to 75 cleg*. . . .0.444 gm 

Heated to 80 deg- 0.420 0.467 

Heated to 95 deg 0.349 

Heated to 100 deg 0.351 

Over 100 deg. C 0.401 

Diminishing amt. ...0.030 gin. 0.054 0.038 0.118 0.111 0.116 
In percentage 6.33 11.39 7.52 25.27 21.22 22.17 

In heating, the proteids also change, peptone is formed and 
tricalcinm phosphate is precipitated. 

The original ferments are especially susceptible to the influ- 
ence of heat. Throngh heating to a certain temperature the 
amylase, the peroxydase, the catalase and the aldehyde reductase 
disappear. The amylase and the aldehyde reductase disappear 
even at a temperature of 65, that is from 50-65 deg. C. Of course 
milk which has been changed in this way by heat must naturally 
be judged differently from a nutritive standpoint than raw milk. 
Out of 3,462 digestible proteids used in each 100 gm. of milk there 
remained undigested: 

In unheated milk 0.762 gm. 

In heating for 30 min. to 80 deg. C. . . .1.153 gm. 

85 deg. C... 1.493 gm. 
90 deg. C... 1.420 gm. 

95 deg. C 1.540 g-m. 

100 deg. C... 1.719 gm. 

Experiments by Briickler, Reiner and Eichloff showed that 
dogs fed for months on sterilized milk showed a good nutritive 
condition, and some of them even manifested a greater gain in 
weight than the control dogs fed with raw milk, but the latter 
were brighter, their blood w^as richer in ash, with diminished salt 
content; it contained more fibrin, had a higher specific gravity, 
and the structure of their bones was more dense and richer in 
ash. The bone marrow of the animals fed with sterile milk was 
more anemic, the periosteum of the bones separated more easily, 
and at times hemorrhages appeared on the borders of the 
diaphyses, such as occur in rachitis. 

The nutritive results in children which have for a long time 
been exclusively nourished on sterilized milk are similar. The 
infants become affected with infantile scorbutus, a symptom com- 
plex, which is known to the physician as ''Moller-Barlow disease,'* 
and which disappears when raw milk is provided. 

From the above it appears that high prolonged heating of 
milk should be avoided, and if possible the advantages derived 
from the heating should be obtained by heating the milk for only 



Pasteurization of Milk. 195 



a short time at a relatively low temperature, which when properly 
applied will appropriately destroy the bacteria. 

The vegetative bacteria may be destroyed by subjecting them 
to the influence of heat at 60-70 deg. C, for one-half hour, or to a 
temperature of 85 deg. C. for a half minute; on the other hand 
it is known that spores of bacteria not infrequently resist a tem- 
perature of 100 deg. C. and over. 

In practice it is advisable to abstain from the sterilization of 
milk with high degrees of temperature, and to apply pasteurization, 
since, through the usual method of sterilization the destruction of 
all germs is not attained and the disadvantages are too apparent. 

The wholesale depots may be provided with outfits for bottle 
pasteurization and milk heating, in which flowing milk, through 
the influence of steam on heating surfaces may be brought to a 
temperature of 85 deg. C. In heating bottled milk it is essential 
to observe that the milk should become uniformly heated through- 
out ; this is attained by shaking the milk during its pasteurization. 
Following this, rapid cooling should be undertaken, which is best 
accomplished by atomizing pipes which cause water to fall upon 
the hot bottles in the form of a spray. 

The apparatuses in which the milk flows over heated surfaces 
should be so constructed that all parts of the milk will come in 
contact with the heated surface, making the heating of the milk 
uniform in all parts. The utilization of the heat in some of the 
appliances is regulated in such a way that the cold inflowing milk 
is warmed by the outflowing pasteurized milk, the latter, however, 
being cooled subsequently. Through the exchange of heat from 
the outgoing stream of milk about one-half of the required heat 
may be saved. The efficiency of some of these apparatuses is 
enormous, since they are able to treat from 5000 to 8000 liters per 
hour. 

From a sanitary standpoint it is apparent that such appara- 
tuses must be so constructed that they may be readily cleaned 
mechanically, since improperly cleaned places conduct the heat 
poorly, and may give rise to contamination of the milk with putre- 
factive bacteria. 

In pasteurization, the same as in milk production, the greatest 
stress should be laid on immediate and thorough cooling, and on 
keeping the milk continuously cool until its consumption, since 
otherwise the pasteurized milk will become spoiled, and will un- 
dergo a form of decomposition which is very undesirable (espe- 
cially in bottle pasteurization). Pasteurized milk decomposes 
through multiplication of protein splitting, peptonizing bacteria 
whose spores may have withstood the heating. The vegetative 
bacteria, among these the lactic acid producers, are mostly de- 
stroyed, and except for a few resistant forms of spore bearers only 
heat-resisting organisms will remain viable, but these forms of 
bacteria are usually harmless (Rullmann, Gerber and Wieske, 



196 .Effect of Heat. 



Buri'i, Russell and IIastiiii>s). These germs decompose proteids 
and carbohydrates by forming butyric acid with gas production, 
and peptonizing the proteids. Boiled milk decomposes more read- 
ily than raw milk from the bacteria which contaminate it after the 
heating process. 

Kelative to the effects of pasteurization, the following should 
be noted : As a result of the effect of 85 deg. C. the bacterial num- 
ber dropped from 10,000,000 to 500 per c. c. These remaining 
organisms however, which consist principally of peptonizing var- 
ieties, multiply rapidly to very great numbers if the milk is brought 
again to 25 degrees C, frequently producing changes in taste, 
which becomes bitter and irritating, but sometimes without mark- 
edly changing either the appearance or taste. 

This however does not render pasteurization hazardous, since 
it is possible through proper handling of the milk to prevent these 
undesirable processes. The marketing of pasteurized milk becomes 
dangerous only when the consumer considers that pasteurized 
milk being free of germs may be kept indefinitely under almost 
any circumstances and therefore takes less care of pasteurized 
milk than he would of the raw product; besides this consumers 
repeatedly heat such milk and thereby diminish its nutritive value 
more and more. It is for this reason that various authorities 
have taken action against the indiscriminate distribution of pas- 
teurized milk. It should be required that the date of pasteuriza- 
tion be indicated on each bottle. 

A statement from the officials of the city of Leipsie asserts that pasteurized milk is 
not more valuable than raw milk, but that it appears to be of lesser value on account 
of the destruction of its raw condition and the consequent chan^oes. Any manipulation 
of milk which claims to extend its keeping- properties by several hours, and which 
possibly may be used in the establishment of false valuation by statements that the 
milk has a lasting-, keeping quality and a freedom from bacteria, is directly dangerous 
and injurious to health if the consumer is not thoroughly informed with regard to the 
effectiveness and limitations of pasteurization. The action of peptonizing bacteria in 
milk that has been pasteurized is pointed out, and recommendation is made against the 
purchase of milk which was pasteurized more than three days previously. The official 
statement also calls attention to Barlow's disease, and to the dangers attending improper 
keeping of such luilk. 

Sometimes pasteurized milk which is never free of bacteria is 
marketed under the attractive declaration of ''free from disease- 
bacteria." What is the relation of pasteurization to such a claim 
as this? According to the experiments of Forster, van Geuns, de 
Mann, Ringeling and Koning, de Jong, de Graaf, and Beck, the 
disease-producing bacteria are affected differently by high tem- 
peratures while in milk than when in bouillon or water. Thus 
for instance heating for a half hour at 70 deg. C. is not always 
sufficient to destroy colon bacteria. Tubercle bacilli are still more 
resistant. According to Kolle and Beck they are not destroyed 
with certainty even when subjected to heating for a half hour at 
80 deg. C, especially not when they are isolated from the influence 



Thermal Death Point of Bacteria. 197 

of the heat by the formation of a surface scum and by coagulation. 
De Jong concludes from his experiments (bottle sterilization) : 

1. That heating for a half hour at 71-72 deg. C. is not always 
sufficient to destroy the tubercle bacilli mixed with the milk. 

2. That heating even to a higher degree does not always give 
satisfactory results since the resisting power of the tubercle 
bacillus varies. 

3. The designation ''free from disease-bacteria" for pas- 
teurized milk is false. 

4. Those who desire milk free from tubercle bacilli must 
purchase sterilized milk, provided it is not obtained from herds 
free from tuberculosis. Bang, de Mann and Forster obtained 
evidence that heating to 85 deg. C, for three minutes destroys the 
tubercle bacilli, a fact which has also been confirmed by the work 
of Weigmann and by the experiments of Tjaden, Koske and Her- 
tel under conditions which prevail in large distributing plants with 
milk from tuberculous udders. Other non-spore-containing dis- 
ease-producers in milk are also destroyed at this temperature pro- 
vided that certain conditions do not prevent proper heating. 

[According to the experiments of Rosenau, it is evident that 
the tubercle bacillus in milk loses its infective properties for guinea 
pigs when heated to 60° C. and maintained at that temperature 
for 20 minutes or to 65° C. for a much shorter time. It should be 
remembered that the milk in the tests of Rosenau was very heavily 
infected with virulent cultures, which was indicated by the prompt 
deaths of the control animals. Milk would practically never con- 
tain such an enormous amount of infection under natural condi- 
tions. It is therefore justifiable to assume that if 60° C. for twenty 
minutes is sufficient to destroy the infectiveness of such milk when 
injected into the peritoneal cavity of a guinea pig, any ordinary 
market milk after such treatment would be safe for human use by 
the mouth as far as tubercle bacilli are concerned. These results 
are substantiated by the findings of Versin, Bonhoif, Th. Smith, 
Schroeder, Russell and Hastings and Hesse. 

Relative to the thermal death point of other organisms Rose- 
nau found that typhoid bacilli are killed in milk when heated to 
60° deg. C. and maintained at that temperature for two minutes. 
The great majority of these organisms are killed by the time the 
temperature reaches 59° C. and few survive to 60° C. 

The diphtheria bacillus succumbs at comparatively low tem- 
peratures. Oftentimes it fails to grow after heating to 55° C. 
Some occasionally survive until the milk reaches 60° C. 

The cholera vibrio is similar to the diphtheria bacillus so far 
as its thermal death point is concerned. It is usually destroyed 
when the milk reaches 55° C, only once did it survive to 60° C. 
under the conditions of the experiments. 

The dysentery bacillus is somewhat more resistant to heat 
than the typhoid bacillus. It sometimes withstands heating at 



]98 ■ Effect of Heat. 



60° C. for live minutes. All are killed at 60° G. for ten minutes. 
However, the great majority of these micro-organisms are killed 
by the time the milk reaches 60° C. 

So far as can be judged from the meager evidence at hand, 60° 
C. for twenty minutes is more than sufficient to destroy the in- 
fective principle of Malta fever in milk. The Micrococcus melit en- 
sis is not destroyed at 55° 0. for a short time; the great majority 
of these organisms die at 58°, and at 60° all are killed. 

Milk heated at 60° C. and maintained at that temperature for 
twenty minutes may therefore be considered safe so far as con- 
veying infection with the micro-organisms tested is concerned. 

Ayers states that the best method of pasteurization at the 
present time, and the one which should be used, is the holder proc- 
ess, in which the milk is held for 30 minutes. For this process a 
temperature of 63° C. (145° F.) is to be advised, since that temper- 
ature gives a margin beyond that sufficient to destroy pathogenic 
organisms, while at the same time it leaves in the milk the maxi- 
mum number of lactic-acid-producing organisms which cause the 
souring of the milk. When using the flash process, the milk should 
be heated to at least 160° F. Since there is almost always a 
fluctuation in the temperature during pasteurization, care should 
be taken to see that the temperature never drops below 71° C. 
(160° F.) in the flash process. — Trans.] 

Exposure at 50 degrees of temperature for 15 minutes or at 
70° C. for 10 minutes is sufficient to destroy the virus of foot-and- 
mouth disease. The virus is destroyed instantaneously at 85 
deg. C. 

All of these advantages may also be obtained from subjecting 
the milk in the household to heating for a short time without 
boiling, when through occasional stirring the formation of the 
scum upon the surface is prevented. Therefore the purchase of 
raw milk, whose fresh condition can be readily controlled, should 
be generally recommended, and the destruction of bacteria should 
then be carried out by simple heating. 

The observation recorrled by Schut appears to be worthy of consideration, namely 
that relatively low temperatures rapidly destroy bacteria, when applied simultaneously 
with a lowering of the pressure. In heating the milk at 70 deg. C. the disturbing scum 
formation was omitted. As accepted by Schut, in this process the steam penetrates 
into the body of bacteria, which explains the more eflScient action of this method. 

Experiments which aim to improve the keeping qualities of 
milk by the addition of chemical substances are very numerous. 
In addition to improving its keeping qualities the retention of the 
raw condition of the milk was attempted. This does not refer to 
the adulterations which are undertaken by dealers for fraudulent 
purposes, or which are carried out in the household, and it should 
be considered that all additions to milk without subsequent decla- 
ration are equal to an adulteration of food, changing it to a spoiled 
product, possibly even converting it into material injurious to 
health. 



Preserving Milk with Chemicals. 199 

At that the additions do not accomplish the purpose for which 
they are intended in the dilutions in which they are used (Richter- 
boracic acid), or they diminish the utilization of milk for cheese 
production because they inhibit the rennet action. Soda or bi-car- 
bonate of soda, boracic acid and borax, more rarely salycilic acid, 
and recently formaldehyde are mostly used. Adulterations will 
not be discussed here, but only earnest scientific experiments will 
be taken up, in which the accomplishment of an actual improve- 
ment in milk has been the object sought. 

1. Budde succeeded in improving the keeping qualities of 
milk with the aid of peroxide of hydrogen. The milk is heated to 
about 50 deg. C, 0.036 to 0.5% H^Os is added and it is then filled 
into bottles and kept for several hours at 50 deg. C. 

According to Lukin it is possible with pure peroxide of 
hydrogen, as indicated by Budde, to give the milk a low bacterial 
count, or render it free of bacteria. Budde 's method has not at- 
tained an extensive use. According to Chick, Rosam, Gordan, 
Bergmann and Hultmann, Eicholz, Nikoll and Duclaux the amount 
of peroxide of hydrogen recommended by Budde is not sufficient 
for the satisfactory destruction of bacteria in milk, but according 
to Lukin their failures were due to the use of impure preparations 
of peroxide of hydrogen. Tubercle bacilli and typhoid bacilli 
were not destroyed by this method. If the authors used 0.1% of 
peroxide of hydrogen, the necessary quantity to produce steriliza- 
tion, then the milk obtained a bitter taste, which disappeared only 
after the excess of hydrogen peroxide had been eliminated by cat- 
alase. According to Utz a small quantity of peroxide of hydrogen 
is retained in the milk even when used in the quantities recom- 
mended by Budde. De Waele, Sugg and Vandevelde, who worked 
with 0.3 and 0.4% of peroxide of hydrogen, have used in addi- 
tion small quantities of defibrinated blood for splitting up the 
retained HoOo. 

Much and Eomer employ a similar method of preserving milk 
which has been obtained under special precautions as to cleanli- 
ness. The milk is filled into sterilized bottles, mixed with 0.1% 
of peroxide of hydrogen, and kept for one hour at 52 deg. C. 
For the destruction of the H2O2 in the milk, hepin, a catalase 
prepared from liver, is added to the milk before its consump- 
tion. Since the hydrogen peroxide milk is very sensitive against 
the influence of light (when exposed to light it very readily be- 
comes bitter, tallowy and rancid), it is best to keep it in green 
bottles and in a dark place. Even with these precautions a change 
in the taste may become apparent after two weeks. 

Injurious action of the peroxide of hydrogen if used in these 
quantities should not be feared; the results in infant feeding are 
supposed to be favorable. 

The milk which is freed from the retained peroxide of hydro- 
gen by the addition of hepin should be immediately used, since it 



200 Effect of Chemicals. 



is no longer resistant to decomposition tlirougii bacterial con- 
tamination, after the liepin has been added. 

2. Years ago von Behring reconnnended the preservation 
of milk by formaldehyde. Experiments upon animals showed that 
the addition of formaldehyde to milk in the proportion of 1:1250 
gave it no ])roperties injnrions to health by any method of appli- 
cation (even intra venonsly), and it was further found that animals 
with a very delicate sense of smell failed to recognize the presence 
of formaldehyde if it had been added to the milk in a dilution 
of 1 :10,000. The action of formaldehyde in such dilution is quite 
marked. The addition of a 1 :10,000 dilution postpones coagulation 
for many days (von Behring, Price and Schaps) ; 1:25,000 and 
1:40,000 prevents coagulation from 1 to 4 days (KoUe). The 
action of formaldehyde was found to be more effective in accord- 
ance witli the cleanliness of the natural milk and this action ac- 
cording to Rothschild and Metter appears to result from the fact 
that the lactic acid bacilli chiefly succumb, whereas the other 
saprophytes are harmed to a lesser degree. Tubercle bacilli are 
not influenced in their viability by these dilutions. 

The feeding of infants for weeks with formalin milk (addi- 
tions of 1 :25,000) may result in an injury of the kidney epithelium 
of the children, which leads to the elimination of albumin. Ac- 
cording to Baudini the rennet pepsin and trypsin action may be 
considerably inhibited by formalin ; the acidity of the milk is 
increased. In the experiments of von Behring the action of 
formalin depends upon its effect in checking the development of 
bacteria, and not on its disinfecting or sterilizing property. A 
concentration of 1 :25,000 up to 1 :50,000 has no influence on the 
t>T5hoid and colon bacteria and staphylococci (Vaughan and 
Schaps). Diphtheria, colon and pyoc3^aneus bacilli have not been 
destroyed even in dilutions as low as 1 :5,000. Tubercle bacilli are 
protected by their waxy covering even against higher proportions 
of formalin, and as a matter of fact formalin is used, on account 
of its action on other bacteria, for the purification of sputum for 
the purpose of cultivating the tubercle bacilli from the saliva. 
Formalin milk constitutes a food whicli should be designated as 
spoiled and injurious to health. 

3. Seiffert worked out a method of milk preservation in 
which the bactericidal action of ultra-violet rays is used for 
sterilization of milk. The method of action of the ultra-violet rays 
has not yet been satisfactorily explained. According to Lobeck 
(cited by Grimmer) the exposure of water to such rays produces 
peroxide of hydrogen. Grimmer believes that the latter is also 
formed in milk, but on account of the catalectic factors of the milk 
it immediately decomposes again. It is possible that the forma- 
tion of peroxide of hydrogen constitutes the germicidal power of 
ultra-violet rays. The milk fat is not changed (Lobeck). Ac- 
cording to Dreier-IIansen the proteid is coagulated after a pro- 



Ultra-violet Rays. 201 



longed exposure of milk to such rays. Seiffert passes the milk in 
broad bottles along the illuminating bodies, allowing the rays to 
act upon the milk for about two minutes. He employed Leyden 
jars fitted with aluminum or cadmium points, which are charged 
with a current of high tension through an inductor which dis- 
charges mutually. Gerber and Hirschli used for sterilization the 
uviol light which is rich in ultra-violet rays 5 he was unable how- 
ever to demonstrate a marked reduction of the bacterial content 
by subjecting a layer of milk of 1 mm. thickness to its influence, 
whereas Finkelstein and Lobeck, Henri and Stodel, Billon and 
Daguerre obtained good results with the ultra-violet rays from 
mercury and quartz lamps. According to Billon and Daguerre 
sterilization may also be accomplished when milk is exposed to 
white light in violet glasses. The action is the best when the white 
light is split up by a prism. 

Eomer and Sames, who also conducted experiments on the 
bactericidal action of ultra-violet light proved that market milk 
which has been exposed to the rays of a Heraus' mercury-quartz 
lamp of 6 ampere strength in a quartz alembic (at a distance of 
15 cm. from the source of light the action of which has been in- 
creased by a reflector) caused a reduction from 98,900 original 
bacteria after one hour of exposure to 16,500 bacteria ; after 1% 
hours to 8750 ; after 21/0 hours to 2,050 bacteria. The taste of the 
milk was pronouncedlv irritating. In a second test the number of 
bacteria diminished from 111,800 to 94,000 in 10 minutes, and to 
65,500 in 20 minutes. On the surface of the milk a yellowish scum 
forms. The peroxydase reaction of the milk is destroyed after a 
prolonged exposure to such light. 

[The experiments of Ayers and Johnson indicate that with 
quartz mercury vapor lamps of the present power and construc- 
tion it would not be possible commercially to completely sterilize 
milk by the ultra-violet rays. 

It might be possible to obtain bacterial reductions as great as 
by pasteurization even on a commercial scale by the use of large 
revolving drums and a number of lamps. However, in milkso 
treated there would be no assurance of the complete destruction 
of pathogenic organisms since the rays do not seem to exert any 
selective'destruckve action on vegetative cells. Of course since 
pathogenic organisms might be assumed to be present in a small 
number in proportion to the total bacteria in milk, if 99.9 per cent, 
of the organisms present were destroyed, it might be assumed 
that the pathogenic bacteria would be destroyed. This process, 
however, would not afford the same security as does proper pas- 
teurization. Then, again, it would be difficult on a large com- 
mercial scale to constantly control the factors which influence tlie 
bactericidal action of the rays. 

It is also doubtful if the lamps could be made to successfully 



202 Effect of Chemicals. 



compete with the present method of steaming milk bottles in order 
to partially sterilize them. 

From these experiments it appears doubtful if ultra-violet 
rays can be used on a commercial scale to replace the process of 
pasteurization. However, it may be possible to use the rays, in 
combination with pasteurization, in the preparation of a special 
milk with a low bacterial count, provided there is a demand for 
such milk in limited amounts for the use of infants and 
invalids. — Trans.] 

4. Other methods of preserving- milk are its saturation with 
carbonic acid under strong pressure, its ozonisation, and its sterili- 
zation with electrical currents. 

The carbonization recommended by Hoffmann, van Slyke, and 
Bosword, the ozonisation advised by Dorn, and finally the steriliza- 
tion through alternating electric currents of high tension recom- 
mended by Guarini and Samarini have not yet attained any prac- 
tical significance. 

The best means of imparting keeping qualities to milk are 
cleanliness in its procurance ; the only method of preservation 
which should be generally permitted for milk is proper cooling. 

This concludes the theoretical consideration of milk. In the 
following chapter the method of control of milk in general will be 
discussed, and finally the method of milk examination will be 
taken up with emphasis on the points which appear especially 
important in the examination of market milk and for the ex- 
aminations of individual samples of milk. 



Chapter IX. 

MILK CONTROL. 

The sanitary police control of foods has advanced greatly in 
importance during recent decades. The study of diseases of 
nutrition in general and the solution of the etiology of these affec- 
tions have resulted in a recognition of the necessity for the estab- 
lishment of measures relative to the quality of food substances, 
and have led to the formulation of laws, ordinances and 
regulations. 

The most extensive development in this relation is shown by the importance of 
the meat -inspection law, which has been advanced to correspond with the value of meat 
as human food. Instead of controlling the marketable meat products in the shops, the 
most important part of the inspection is placed at the point of meat production, that 
is, in the abattoirs. With the exception of the so-called home slaughtered meats, not 
a single pound of meat is consumed or used for food products in Germany, without 
being first subjected to inspection. 

The meat consumption per capita in Germany in recent years 
has amounted to from 103 to 110 lbs. In addition to the value of 
the meat produced, the amount of milk consumed should be con- 
sidered, there having been made an approximate estimate of an an- 
nual production of 7 billion gallons of milk, the smaller portion of 
which is utilized as drinking milk, the larger part for the manufac- 
ture of milk products as cheese, butter, etc. 

According to statistical compilations, in 1905 the quantity of 
milk consumed per capita amounted 

in Berlin to 106.5 liters (30 gal.) 
in Munich to 131.5 liters (37 gal.) 
in Hamburg to 137.5 liters (38 gal.) 
It is gratifying to note that the consumption of milk in Munich 
has' increased during the last decade, and when its nutritive value 
is considered its low cost as a food stuff is quite apparent. The 
amount of milk and meat consumed in Munich per capita is as 
follows : 

1900 : Milk 130 liters (36 gal.) Meat 81.8 kg. (180 lbs.) 
1904: Milk 131 liters (37 gal.) Meat 75.1 kg. (165 lbs.) 
1908 : Milk 149 liters (41 gal.) Meat 85.9 kg. (189 lbs.) 
and without doubt milk consumption will still continue to increase 

203 



204 ^rilk Control. 



if the cost of all other foodstuffs continues to rise. There arc no 
means by ^^ilich the imtrition of the people conld be increased to 
better advantage than by increasing their consnniption of milk, 
since it has not yet reached the high point warranted l)y the valne 
of milk as a nntritive snbstance. 

From the various discussion in this work, the importance of 
supplying consumers with milk of good quality is apparent. An 
increase in milk consumption is of equal importance to the interest 
of the nutrition of the people and to the interest of agriculture. 
This increase however can only be obtained when, in addition to 
an educational propaganda regarding the nutritive value and cost 
of milk, care is taken to rectify the generally existing evils attend- 
ing its production, by which means the milk will be brought up to 
a standard, which may reasonably be required of any food. There- 
fore it should not only be unadulterated but must be produced and 
delivered in a clean manner, in an unspoiled, fresli condition, and 
possess no disease-producing properties. 

The important sigiiifir-ance of liealtliy milk as food for the people, especially for 
infants, has been emphasized by physicians, hygienists and veterinarians in numerous 
special articles, which have argued for and against the desirability of gaining nutrition 
through the use of market milk. Public interest and private philanthropy have 
accomplished a great deal of good by the establishment of infant milk depots. Such 
establishments are frequently attached to the abattoirs, and are conducted under the 
successful direction of veterinarians. It is impossible to enter here into a discussion 
of such establishments, since this field constitutes only a small branch of the great 
question of the milk supply. 

While the determination of the causes of the so-called dis- 
eases of nutrition may not yet be sufficiently clear, the general and 
local surroundings of the patient or other conditions may influence 
the course of these diseases. This is particularly true in summer 
mortalities of children, as in these diseases various conditions, such 
as want of natural nutrition, faulty housing, etc., may all play a 
part as factors. Nevertheless, from the experience of specialists 
the conclusion must be drawn that a strict sanitary police con- 
trol must be established in order to protect human health as much 
as possible from the ills occasioned by dangerous milk. 

Such harm may result from the consumption of: 

1. Milk from diseased animals, 

2. Milk originally wholesome but which has been subse- 
quently contaminated with bacteria pathogenic for man, 

3. Milk, which has been spoiled by any kind of decomposi- 
tion, or which is beginning to spoil, 

4. Milk containing chemical preserving substances. 

These are briefly the points which in themselves prove the 
value of hygienic control of the milk traffic, and their elimination, 
witli as much consideration as possible for the economic impor- 
tance of the various factors, must be constantly kept in mind. 

A proper execution of sanitary police regulations governing 
milk traffic is not only of importance for the health of the people 



Advantages of Milk Examinations. 205 

but attains even greater value for the milk industry and general 
agriculture through the indirect advantages which result from 
their enforcement, such as the improvement of the herds, etc. 
Measures which are in perfect accord with the hygienic require- 
ments of milk traffic, are at present enforced by most cities, which 
have adopted various forms of ordinances and laws to cover this 
subject. Some of the states and the federal government also pro- 
vide for certain additional control. 

The milk control stations of several cities in Germany have 
attempted to produce an improvement of the milk traffic by the 
establishment of proper ordinances. Even the best organized 
stations confine themselves almost entirely to the control of the 
finished product offered for sale, and therefore they are limited 
to the examination of samples. If the existing distribution of milk 
and extension of deliveries in large cities are considered it would 
require an army of officials to take samples and examine them, in 
order to test all the milk delivered to ascertain its value as food. 

Even in the eventual centralization of the milk traffic, ap- 
propriate examination of market milk from a hygienic standpoint 
will be impossible, since in each shipment too many questions 
would have to be solved, and besides this, Ave have not at our com- 
mand reliable methods for examining the finished market milk 
rapidly and thoroughly. 

The advantages of market milk examinations, which should 
not be underestimated, consist in the fact that it is possible to 
detect gross neglect and wilful violations, by which in many cases 
guilty parties may be held responsible. The knowledge that he 
is under observation, and the fear of punishment compel even the 
most indolent milkman and dealer to give increased attention 
to production and handling, including transportation. In some 
cities of Germany a great deal has been accomplished in the con- 
trol of market milk, but an effective improvement is prevented by 
the existing methods of milk officials. Whatever has been ac- 
complished through the control of market milk, it is slight when 
compared with the requirements of the law and regulations. If 
milk control is confined in a one-sided way only to adulteration, 
preservation and to the dirt content, or to fermentation tests and 
acid content, as they are mostly practiced, it is hardly possible to 
expect proper improvement from a hygienic standpoint. 

Food chemists have been the chief officials engaged in milk 
control up to the present time, since the principal stress has been 
laid on the detection of adulteration or of attempts to improve 
milk by the use of preservatives. The author considers it as ab- 
solutely essential that this field of control should continue in 
charge of chemists, since the physico-chemical properties of milk 
require a great amount of special training if the results obtained 
by examination are to be subjected to critical judgment. ' This 
however does not infer that veterinarians, physicians or other 



20G Milk Control. 



persons who have obtained special training liave not the same 
right to take up the work against violators. It is immaterial who 
executes the work if it is only carried out properly. Chemists, 
veterinarians and physicians have their special sphere of activity 
in milk control, and all should work in harmony that they may 
accomplish the desired results, each profession exerting all its 
power towards improvement of the milk supply from the time 
of its production until its distribution to the consumer. It is 
deemed advisable to introduce here a short description of milk 
control in the City of Munich : 

The beginninp: of control in Munich can be traced back to 1834. Police authorities 
brought to the police physician samples for examination. With the taking over of food 
inspection by the magistrate in 1862, market inspectors, and in 1876 district inspectors, 
■were detailed to take samples and to make the preliminary examinations under the 
direction of district veterinarians. The latter were required to carry out the scientific 
examinations and to pass judgment on the samples. 

By an agreement of hygienists, food chemists, dairy experts and agriculturists, 
the latest local police measures were inaugurated in 1906, and at the same time the 
inspection forces were reorganized. 

The city was divided into six control districts, and the inspectors assigned to these 
districts had to carry out the requirements of the authorities and the experts relative 
to the supervision of the milk traflfic. The scientific part of the inspection is conducted 
in the corresponding divisions of the examining station, that is in the chemical and the 
veterinary bacteriological divisions. Assistant inspectors are assigned to the inspectors 
for aiding them in the work and for the transportation of the samples. The inspectors 
are required to supervise the execution of the regulations and to report any violations 
of these measures to the milk control station. The supervision should be adapted as 
far as possible to the hours in which the business, sale and operation of the milk 
establishments are carried on, but may be carried out at all hours of the day and night, 
and it should be so regulated that the dairies at no time could feel safe from the restraint 
of supervision. The duty includes: 

1. The control of and supervision over all milk brought into the city, all milk 
which is in traffic within the city, all transportation containers, all dairies, milk shops 
and production establishments within the city limits, and the taking of samples. 

2. The procuring of necessary milk samples for examination, both from stable 
and salesroom, and of other material necessary for evidence. 

3. Conducting research work in individual cases, and making out reports and 
complaints. 

All collected samples of milk, samples of other food substances which are sold 
in the dairy, milk cans which do not correspond with the regulations, various containers 
in which the milk is kept, measured and sold should be submitted at the milk control 
station for opinion. A report should be made on the fittings and condition of the 
rooms and premises where the milk is stored, and from which it is distributed. The 
transportation of the milk samples to the official milk control station should be accom- 
plished immediately after the sample is procured. A preliminary examination precedes 
the taking of samples by the inspectors, which consists in an examination by the senses 
(appearance, odor), and in the use of the laetodensimeter and thermometer. The trans- 
mission of the samples to the scientific division is accompanied by forms on which the 
results of the preliminary tests are indicated, and they also give the date, hour, place 
of collection, origin of the sample, name of the dealer or producer, number of the 
sample, and its relation to a certain case. 

The samples are immediately examined in the scientific division, the inspectors 
are informed of the results as soon as possible, and their subsequent procedure in 
special cases is indicated by the recommendations of the experts and the director of the 
station. 

If stable control and the taking of samples in a stable outside of the city limits 
appear necessary, or if such are suggested by the scientific workers of the official milk 
control station, the inspector obtains these samples after obtaining, through the city 
authorities, permission to go upon the premises. In taking samples in a stable the 
princii^al stress must be laid on the dairy management and therefore preliminary tests 
of the samples taken in the stable are eliminated. The scientific experts attach their 



Co-operation of Officials. 207 



opinion to the reports of the inspectors, the full report, with the result of the researches, 
being transmitted through the official control station to the magistrate, who, depending 
on the case, transmits the material to the proper courts. ^ ■,.... 

The separation of the laboratories into a chemical and a bacteriological division 
has already been briefly mentioned. The chemical division examines for simple and 
combined adulteration by the addition of water, removing of the cream, or both by 
establishing the specific gravity, the fat contents, calculating the amount o± to.al 
solids and the fat-free solid content, determining the refraction index of the milk 
serum by the nitrate test, testing for the degree of acidity and testing for other 
chemical adulterations. The bacteriological division examines as to fitness tor ccra- 
sumption by establishing the purity, odor, taste, consistence, age and freshness, the 
raw condition, intermixing with secretion of animals with affected udders, etc. ihe 
procedures of each division are kept separate as much as possible, and this separation 
of the divisions has proven of splendid advantage. Co-operation between these divisions 
when the work overlaps, and mutual support aid in the success. 

Owing to the activity of the official milk control station it was 
soon noticed that marked adulterations had become very rare, 
and that objections and condemnations on account of gross con- 
tamination were reduced to a minimum. Considerable objection 
still exists relative to the transportation cans which are frequently 
used in a most insanitary condition. The regTilations relative to 
the proper closing of the cans are now almost uniformly observed. 
The acid content of the milk is only exceptionally increased by 
fermentation, and the spoiled milk originates usually from milk 
collecting establishments and cheese factories, whereas individual 
producers as a rule supply fresh milk. The increased degree of 
acidity is traced in most instances to improper cooling, dirty trans- 
portation cans, mixing of fresh and old milk and adulteration with 
skimmed milk. Preserving agents scarcely ever come into con- 
sideration in Munich. 

It is to be regretted, however, that the limits of milk control 
activities have apparently been attained, in so far as they concern 
the testing of milk ready for consumption. Nevertheless, attempts 
have been made by extending the control to the stable and to the 
producing animal in order to further improve the milk supply. In 
certain cases good results have been obtained through giving in- 
structions and warnings as to the requirements, or at least in ad- 
vising the adoption of all precautions which are possible in prac- 
tice, for instance in the streptococcic mastitis question, which this 
city was first to take up on practical lines on a large scale. The 
results attained are by no means to be underestimated, but while 
there is no doubt that with the hard battles considerable results 
have been obtained for the moment among a small percentage of 
the producers, still no one can offer a guarantee that even on the 
morrow the same conditions will not prevail as formerly, and in 
this lies the insufficiency of market milk control and of the system 
of taking samples from time to time. In the future other measures 
will have to be given consideration in sanitary milk inspection, if 
it is desired that conditions which are frequently intolerable, and 
which prevail at present in the milk industry, should be eliminated. 

A guarantee of good and harmless quality for market milk 



2(1S Milk Control. 



forms an absolute liygionie reqivireiiiont, and at the same time it 
is the prerequisite for increasing- milk consumption to its full ex- 
tent. This can be attained only through strict lei^ridation and 
flawless supervision of the milk from the bei>innino' of its produc- 
tion up to the time of its delivery, taking advantage of the great 
progress which has been made by science in recent times. 

Milk hygiene must connnence in the stable. A perceptible 
step in advance is gained by the introduction of stable super- 
vision. The preliminary requirements for the production of un- 
objectionable milk are healthy milking animals, healthy udders, 
healthy milkers and clean utensils and surroundings. In this in- 
stance the veterinarian is the jiroper counsellor, his preliminary 
training offering the necessary assurance that these requirements 
for well-managed dairy business will be fulfilled. Besides the ex- 
amination of the health of the cows, the supervision must be ex- 
tended to the care of the animals, stable conditions, and the keep- 
ing and feeding of the animals. The necessity for the most strin- 
gent cleanliness in milking and for the careful preparation of the 
milk by means of filtration, and cooling must always be impressed 
upon the dairyman, as well as the necessity for satisfactory 
transportation. 

Some hygienists consider the processes of decomposition 
brought on by contamination and improper treatment of milk as 
especially important causes for the rapid spoiling of milk. The 
author considers that their special significance should be laid, in 
cases of milk poisoning the same as in meat poisoning, to those 
disease-producers and their products which prove toxic in the 
animal body, and which originate in the milk-producing animal. 
The veterinarians prove their value in sanitary police supervision 
of milk production, by seeing that the cities are supplied with good 
milk, suitable as food for infants, and by watching the dairy indus- 
try. This supervision at the site of production produces better 
results than the most painstaking and well organized inspection of 
the finished product. The great dangers which threaten man 
through the causative agents of septic metritis, acute and chronic 
mastitis, enteritis, etc., are considerably reduced. The control 
of the milk traffic and milk industry requires especially the co- 
operation of all factors which come into consideration. Until uni- 
form regulations for sanitary police supervision are established it 
will remain the duty of veterinarians and physicians to point out 
the importance of hygienic measures to the producers through con- 
tinuous education, indicating also the economic advantages which 
ma7y^ be gained for their own interests. In northern Bavaria the 
supervision of stables, dairies and distributing stations has already 
been inaugurated by the employment of district dairy inspectors. 

Through periodical stable inspections considerable advance- 
ment could be made at the present time. This supervision should 
not only include the so-called certified milk or infants' milk, but 



Supervision of Milk Production. 209 



also the production of all milk consumed, since the largest pro- 
portion of the parents of infants and consumers in general cannot 
purchase certified milk, and the children of this class who cannot 
afford to buy certified milk are the ones principally exposed to the 
dangers of infant mortality. Such classifications of milk may be 
of advantage to the milk trade, but they must not be taken into 
consideration by sanitary officials who are supervising the milk 
traffic. We are clear with regard to the ultimate aims which we 
must bear in mind in the sanitary police supervision ; whether these 
aims will ever be realized is a question of economic and social con- 
ditions. At the present time the attainment of the ideal goal_ of 
flawless supervision of milk from its production to its consumption 
is made very difficult by these very conditions. As long as the 
cheapness of milk as a food product for the masses stands m the 
foreground in the interest of the people, a place in which it actually 
must stand, a proper, thoroughly organized control of the pro- 
duction can hardly be inaugurated. 

Eeeommendations for sucli control have teen made by Meinert and others, and 
recently by Schern. For an effective execution of control over the production of milk, 
supervision must be established in both city and country. Milk is produced not only 
in the countrv but also in the city. All milk produced must be subjected to uniform 
control. Within these districts of control the milk-producing cities should therefore 
be included. A veterinarian periodically examines the dairy herds and the milk ot 
each animal, the individual animal in these districts, etc., without previously giving notice 
to the owner of the animals as to the time of the inspecton. In this inspection the 
milkers are also observed as to their state of health. The procured milk is examined 
to see whether it is clean and sufficiently cooled. The stables are examined to determine 
whether they meet the requirements as to light, ventilation and cleanliness. _ The control 
of production is linked with the supervision of transportation in certain milk-collectmg 
places, and finally the inspection of the dealers at the place of consumption follows. 
Such a complete supervision is not considered possible in practice without considerable 
increase in the cost of the product, and this should and must be avoided. The sanitary 
milk officials will have as their most important duty the finding of ways and means for 
the practical execution of supervision, which may be accomplished without great 
economic losses of production and efficiency, and without injuring the other factors 
in the milk industry. Meinert believes in the possibility of supervising the places of 
production under supervision of the state, by the appointment of physicians, veterinarians 
and practical agriculturists for this purpose. 

For each township the milk producers should select trustworthy men as supervisors, 
who by means of frequent examinations at the time of milking should -convince them- 
selves of the manner in which the requirements of the legislative measures are being 
observed. The activity of these supervisors should be principally along educational 
lines. These men should call the attention of the owners to existing deficiendes m 
the management of the dairy, they should offer remedies to eliminate these deficiencies, 
and after the lapse of a certain time, they should satisfy themselves that their advice 
has been carried out. In ease of disease of the dairy cattle it should be reported to 
a veterinarian for consultation and judgment. The supervisors should be instructed as 
to their duties by the official veterinarians. Creamery corporations could select their 
- own supervisors instead of depending on the local supervisors for the inspection of the 
dairies producing milk for their plants. Larger establishments could voluntarily subject 
themselves to direct state control. Besides this practical supervision, the district 
veterinarian should examine the animals every three months as to their condition of 
health, and judge the character of their milk. Persons who are connected with the 
procuring and handling of milk should be placed under the control of an official physician. 
The producers, supervisors, milkers, and all persons connected with the dairy should 
be examined as to the possibility of. their transmitting human diseases to the consumer 
through the milk acting as an intermediate host, and the supervisors should report their 
observations as to any sickness among the attendants to the physician m authority. 
The entire system is subject to control bv the state, which appoints its own officials 
for larger districts to carry out the supervision of the work. 



210 Milk Control. 



It must always be considered that the populace has an interest 
not only in the prociirance of unadulterated and unspoiled milk, 
but also in having the milk marketed at such a price that it may 
remain accessible as a product of consumption for the masses, and 
if possible its consumption should be increased. Accordingly too 
far-reaching', stringent requirements should be avoided, as well as 
all requirements that cannot be met bj^ the prevailing condition of 
production, on account of financial and technical grounds. Healthy 
dairy cattle and the best possible cleanliness of the stables and 
surroimdings are more important than special feeding regailations, 
or requirements for stable buildings which the small farmer is not 
in a position to adopt. In order to prevent too stringent, or one-. 
sided requirements altogether, the adoption of a uniform standard 
would be necessary for the entire countrj^, and each state could 
establish its own regulations which would conform with the con- 
ditions of that particular localit}^ The introduction of the terms 
"inferior value" and ''conditionally passed" for certain low 
grades of milk would reduce the economic loss which results from 
the use of the terms ''spoiled," and "injurious to health." 

If stable inspection is inaugurated, a thorough organization 
may conduct a supervision by which the owners of small herds can 
also comply with the requirements. The present system of milk 
inspection not infrequently fails to include such small dairies be- 
cause the supervision of the entire milk traffic is extremely dif- 
ficult, but with the introduction of stable inspection the enforce- 
ment of hygienic requirements that shall include the small pro- 
ducer will be found to be not only practicable, but also very de- 
sirable. Dairy associations and contractors mtli co-operative 
creameries should regulate fluctuations of deliveries and consump- 
tion, so as to provide the best possible utilization of the excess of 
production, or the milk which has been declared by the city in- 
spectors as unfit for drinking purposes may be conditionally passed 
if desig-nated as inferior milk. 

Such a system has been adopted by the dairy association of 
Hamburg, in order to meet the economic losses caused by the 
stringent enforcement of the milk inspection regailations. 

The author believes that with legislative regulation of milk 
inspection, and especially with supervision of the production, it 
will be possible, even with the newly created conditions, to supply 
the population with good, clean, wholesome milk at relatively low 
prices. With good will and co-operative work, as well as with con- 
siderate enforcement of the regTilations, the desired goal may pos- 
sibly be reached within a short period of time. 



Chapter X. 

MILK INSPECTION. 

(a) Taking of Samples. 

1. Market Milk. The taking of tlie sample must take place 
only after the fat of the cream gathered during transportation has 
been sufficiently distributed through shaking or stirring. Especial 
attention is required when separation has occurred through 

freezing. ., ,, i , 

2. Stable Samples. The inspector who takes the sample must 
have his whole attention directed to the production and handling 
of the milk, as the people suspected of adulteration often display 
unbelievable slyness in order to deceive the inspector. Particular 
care should be taken that the mixing tank or vat does not leak, 
that the milk pails and other vessels do not contain wash water, 
and that, during the milking, the milk is not adulterated with water 
from bottles hidden in the clothing of the milkers ; it is important 
that the milking should be complete. 

If nitrate has been found in a suspected sample, a water test 
for nitrates should be made from each well at the place of 
production. 

Only after milking, are inquiries to be made regarding the 
feeding, keeping, care, and condition of the individual animals, etc. 

The stable samples must be thoroughly mixed. 
- 3. At least I'o liter should be taken from each market or 
stable sample, in" order to have sufficient material for all 
examinations. 

4. When the samples have to be carried a long distance to 
the place of examination, they must be preserved with . 1% forma- 
lin. For chemical examinations 0.1 fo of potassium bichromate 
is permissible, which is obtained by the addition of a 1% solution 
to 100 parts of milk. The addition must always be_ stated. 

For bacteriological examinations, the preservation of the sam- 
ple is not permitted, except in cases where a microscopical exam- 
ination only is desired for the determination of inflammations of 
the udder or the presence of tuberculosis. 

211 



212 ^lilk Iiisi)ec'tioii. 



5. The sample bottles nnist ])e filled Tip to the neck, in order 
to prevent the foi-mation of butter during- transportation. 

6. The bottles should be closed so that an unauthorized open- 
ing is excluded. 

The transportation to the place of examination must take 
place as soon as possible after the taking of the samples, and if 
transported by rail, sufficient packing should be provided to pre- 
vent breakage of the bottles. 

If samples are desired from individual cows and not market 
or mixed milk samples, smaller amounts, for instance, 100 gms. 
or less, are sufficient, provided that only an examination for in- 
flammation of the udder is involved. With samples taken for 
chemical examination from individual cows, a complete milk- 
ing is necessary for satisfactory results. If examinations as to 
changes of milk through diseases are to be made, at least y^ liter 
must be sent in from each milking until the day after recovery. 
In certain cases, for instance, with emergency inoculation in foot- 
and-mouth disease, the taking of samples must begin before the 
inoculation and continue until complete recovery. 

"When examinations for inflammation of the udder are desired^ 
the sample of milk may be poured into a reagent glass by means of 
a dipper, which must be thoroughly cleansed after each sample, 
or, the samples are taken in such a manner that in pouring the 
milk from each cow from the milk pail into the cooler, the opening 
of the reagent glass is kept in a position to fill the glass. 

In taking samples from each quarter, it is advisable to milk 
the secretion of each quarter in a cleanly manner into the reagent 
glass. The sample is taken from the middle milking, that is after 
the quarter has been partially milked. All samples have to be 
accurately marked according to cow and quarter. 

In protracted examinations, for instance, for the detection of 
tubercle bacilli, it is recommended to divide the animals of large 
herds into groups, and to collect the milk from each five or ten 
cows into a sample bottle. 

For the determination of dirt in milk, which rapidly sinks to 
the bottom, it is recommended to take an average sample from the 
well-mixed milk, and allow the sediment to settle in a separate 
container, which is examined after the milk is poured off. 

After arrival at the laboratory, the samples must be examined 
as soon as possible ; however, until the examination, they must be 
kept in the ice-l)Ox or in the cooler. 

(b) Examination of Milk. 

The veterinarian may have to perform the preliminary testing 
of milk as to adulterations, but he will especially have to consider 
the changes in milk which are caused by animal diseases, inflamma- 
tion of the udder, or he has to pass judgment on possible changes 
caused bv certain external or internal influences. A final opinion 



Adulteration. 213 



should never be given, except after a most intimate knowledge of 
the special conditions. 

Milk mixed from many cows has to be judged differently from 
milk of one or a small number of cows, because in the latter case 
the fluctuation through internal or external influences may be very 
marked, whereas the presence of abnormal secretions from one or 
several cows is either modified or concealed through mixing their 
milk with that from many healthy cows. 

An adulteration should never be estabhshed or the degree _ot 
adulteration calculated, without making comparative tests of satis- 
factory samples from the same source. A definite diagnosis of the 
degree of adulteration based merely on the values of accepted 
averages, normal or experimental, would be erroneous, of which 
no scientific milk inspector should be guilty. 

Before the beginning of the examination, each sample should 
be sufficiently mixed by shaking, without having any considerable 
amount of air shaken into the milk. 

The testing of milk is divided into the preliminary examina- 
tion and the special scientific examination. 

Through tests by means of the senses milk is first examined 
as to the color. Adulterated market milk is often bluish, and 
secretions from animals with udder diseases often make the milk 
reddish. . 

The odor is determined either immediately after emptying 
the cans or in the laboratory by heating the milk in glass beakers 
up to the formation of steam. The odor of good and palatable 
market milk may even vary considerably. If, however, special 
odors are very conspicuous, the presence of certain milk defects 
must be considered, possibly as the result of bacterial action. 

The consistence of the milk should not be too thin or watery, 
(suspicion of adulteration), and neither should it be sticky, slimy, 
greasy or curdling, which changes indicate diseases, particularly 
udder affections, or the presence of certain bacteria of milk which 
have propagated since the milk was secreted. 

A fine vesicular foam appearing after shaking should rapidly 
become large bubbles and disappear. The remaining fine vesicular 
foam is the result of shaking soapy milk. 

The taste is to be judged in the same manner as the odor. The 
milk should be delivered and sold in a cold condition, and therefore 
in the collection of all samples of milk the temperature should be 
ascertained. 

With market milk the positive result of the boiling test, that 
is when the milk curdles, is a sign of advanced decomposition (10 
to 12 degrees of acidity according to Henkel-Soxhlet). 

With the fresh milk of individual cows, curdling after boiling 
indicates inflammation of the udder, the curdling being mostly 
limited to the milk of individual quarters or to the colostral milk 
at the beginning or at the end of lactation. 



214 Milk Inspection. 



The alcohol test also curdles market milk wliieli lias become 
spoiled (8 to 9 degrees of acidity), 

A positive reaction with fresh samples from individual cows 
or with samples from separate quarters indicates either a physio- 
logical or severe pathological inflammatory condition of the milk 
glands. The milk is mixed with an equal amount of 68% alcohol. 

Kecently, the alizarol test has been reconunended for the de- 
tennination of spoiled milk. Milk mixed with an equal part of 
alizarol becomes brownish violet, as long as it is fresh and not 
spoiled ; otherwise the color turns brown and yellow, and the milk 
curdles, with the formation of thick flakes. 

For the control of market milk or for the diagnosis of udder 
diseases the author found that the alizarol test (milk with 68% 
alcohol and as much alizarin as is soluble) is without any value in 
testing samples of individual cows or quarters. 

The degree of acidity of the milk is established by titration 
with standard alkali. 

1. According to Henkel-Soxhlet, with ^ normal sodium hy- 
drate solution, fresh market milk has about 6.0 degree of acidity. 

2. According to Thorner and Pfeifer, with tV normal so- 
dium hydrate solution in 10 c. c. of milk and 20 or 40 c. c. of water, 
respectively, with 5 drops of a 2% solution of phenolphthalein 
(the figures thus obtained are multiplied by 10) fresh milk has 
about 18 degrees of acidity. 

According to Henkel-Soxhlet, the acidit}?- is determined by 
titrating 50 c. c. of milk, to which 2 c. c. of a 2% alcoholic solution 
of phenolphthalein have been added, to a faint but permanent 
pink. Each % c. c. of alkali (i/4 normal sodium hydrate) corre- 
sponds to a degree of acidity. 

Scliern utilizes 10 c. c. of milk and titrates drop by drop with 
1/40 normal sodium hydrate solution after having added 1 to 2 
drops of the solution of phenolphthalein. The titration takes place 
in a mixing cylinder Avhicli is so graduated that the difference of 
the level of the fluid before and after the titration shows the degree 
of acidity. 

An increased degree of acidity in market milk, for instance, 
7 or more after the method of Henkel-Soxhlet, does not always 
indicate a spoiled condition. This can only be presumed when the 
increase of acidity in a certain time and at a certain temperature 
is very rapid, in other words, when the curve of acidity is abrupt. 
After 12 to 24 hours the degree of acidity is again determined. 
Fresh milk, kept at 20 degrees C, shows from 10 to 15 to 20 de- 
grees of acidity after 24 hours. Milk at the end of the incubation 
period, before bacterial multij)lication begins, has 25 to 30 degrees 
of acidity, and old milk 30 to 40 degrees. The increase in degrees 
of acidity between fresh milk and older milk is caused by the for- 
mation of lactic acid. One c. c. of 14 normal sodium liydrate=22.5 
mg. lactic acid, and 1 c. c. of xu normal sodium hydrate=9 mg. 



I-Ioyberg's Test. ^15 



lactic acid. In spite of this, the degrees of acidity of Henkel^ 
Soxhlet cannot be computed into the degreesof acidity of Pfeifer 
because through dilution with water the solution of slightly soluble 
phosphates decreases the degrees of acidity obtained anc^ there- 
fore, the degrees of acidity of Thorner and Pfeifer show lower 
vabie^ than those of Henkel-Soxhlet. 

Milk from individual cows often have greatly decreased or 
increased degrees of acidity. The decreased, ^r, more rarely in- 
creased degree of acidity of a single sample creates tjie su^Pic^^^^ 
that the cow is suffering from udder disease. Hf h f iditj of all 
four quarters is present with colostrum and m milk of fresh cows. 
The S from cows at later periods of lactation is frequently 
alkaline and has a lower degree of acidity. 

Dropped on litmus paper, market milk shows an amphoteric 
reaction. Alkaline reactions of single samples must be judged 
the same as low degrees of acidity. If market milk ^liows an a ka- 
line reaction, an alkali may have been added for Preservation. 
The reaction of market milk is acid to rosohc acid On the aclcli- 
tion of alkali to milk, the milk, upon adding rosoic acid-alcohol 
turns rose red. With fresh single samples of milk the red color 
after the addition of rosolic acid-alcohol is an indication ot the 
presence of inflammation of the udder; cows m the late periods 
of lactation may also show red coloring of the milk. 

To lacmoid the milk is alkaline, and also to dimethyl orange. 
The so-called Hoyberg test to determme - fibrin and pus in 
samples of milk from individual cows is based on the difference 
in the reaction of the milk. mt /• v -t i 

The test is conducted so that 5 c. c. milk (individual cows or 
quarters) are mixed with 5.5 c. c. solution of rosolic acid ^^dllch 
is prepared from 0.45 c. c. of a 1% solution 5 c. c. plus alcohol. 

A positive reaction to the test creates suspicion while a nega- 
tive result does not exclude it. . ^ ^ ^^ -^ 
As the reaction of milk from diseased quarters frequently is 
perfectly normal or acid, the test does not compare with the 
Trommsdorff test, and especially the microscopical examination.. 
Besides, it is very difficult to distinguish the fine differences m the 

color shades. . „ „. ,,, ^ ^^-, 

The determination of the alkalinity of milk with to noimai 
acid has so far not been adopted in practice. ^ 

- The dirt content of milk should not be weighed, as recom- 
mended by Eenk, since the amount of visible foreign material 
should not determine the disposition, but rather its quality 
should be considered. Besides, much dirt is dissolved m the milk, 
which neither can be determined through filtration nor through 
weighing the filters. The amount of dirt is estimated m degjees, 
through the sedimentation method or through filtration, and tne 
quality is thus determined; as a rule it represents remnants ot 
feed, feed dust, portions of litter, manure of cows, cow hairs, etc. 



216 Milk Inspection. 



From the iniifonnly fine or coarse particles of dirt in milk, or 
from the presence of cow hair in large amounts and larger par- 
ticles of dirt, it may be determined whether the dirty milk has 
been strained after the milking-. 

Tlie filtration methods in which disks of cotton are used as 
filters have an advantage in that they indicate more distinctly the 
actual content of dirt than the sedimentation methods, where a 
considerable proportion of the dirt is drawn up into the cream 
during- the separation. The author uses an apparatus in which a 
disk of cotton is hold in a simple plate-shaped filter, over the vessel 
into which the milk is to be poured. The cotton disk is pressed 
into the filter by a glass cylinder, as is the case with the apparatus 
of Fliegel and Bernstein. At the present time such dirt testing- 
apparatus may be purchased from nearh- all dealers. For the 
household and for small amounts of milk certain filters are recom- 
mended like those in which the filling- funnel represents a bottom- 
less bottle, to the mouth of which a ring and a wire strainer con- 
taining a disk of cotton are attached, by means of a wire fastener. 

Henkel's control filter is also based on the principle of filtra- 
tion through cotton by which an angle-shaped segment of the filter- 
ing- disk remains free from dirt in order to control the purity of 
the milk. The same result is attained with other methods where 
the border of the filtering- disk remains free from dirt. 

At the places of official examination of milk distinction is 
made between slight, moderate, strong, very strong, and exception- 
ally strong- pollution, and the milk accordingly is judged as either 
clean or spoiled or even injurious to health. 

Market milk may be tested at receiving- stations either by 
drawing up samples from the bottom of the cans with the aid of 
long pipettes, or, as is customary in Munich, by pouring- the milk 
from the original can into another vessel The residue of the milk 
in the first case is taken as a sediment sample, while an average 
sample is taken from the mixed milk of the second container in 
order to make a quantitative estimation. 

Trommsdorff 's test is splendidly adapted to the detection of 
finely divided particles of dirt, the heavy particles being collected 
in a capillary tube. 

The methylene blue reductase test gives very good information 
relative to bacterial multiplication. A solution of methylene blue 
in water, serves as a reagent, consisting of 195 parts H2O and 5 
parts saturated alcoholic methylene blue solution. The test is con- 
ducted by placing 20 c. c. of milk and 1 c. c. of methylene blue 
solution in a reagent glass at 40° C. and the time is determined in 
which the sky blue mixture becomes completely white. Milk which 
becomes white in less than 3 hours is already old. The age, how- 
ever, does not refer to the hours since its production, but means that 
the milk has "aged." Milk which is obtained in a dirty condition, 



Reductase Test. 217 

lias not been cooled, and lias been transported in poorly cleaned 
cans, ages more rapidly than milk which has been properly treated. 

In making the test it is not necessary to cover the sample in 
the reagent glass with boiled oil or kerosene since there is no 
advantage in such a procedure. In the same way the ''reductase" 
which is recommended by commercial firms is of no advantage. 

Fresh milk from individual cows may be rapidly reduced 
owing to the large content of cells. 

Very valuable results are obtained with the reductase test 
when conducted in connection with the microscopic examination of 
the sediment. 

Frequently, in the testing of the centrifugal sediment, large 
numbers of bacteria are found not infrequently agglutinated in 
colonies, and the milk, in spite of the apparently high content^ of 
bacteria, has very little reducing power. This is an indication 
that the milk has been transported in uncleaned cans, but does 
not in itself prove decomposition. 

Microscopically in the residue of milk in the can are found 
milk souring bacteria, diplococci, streptococci, sarcines, besides 
oidia, coli, and rods. 

Such is also the case when the milk is obtained under dirty con- 
ditions, but is promptly delivered. 

The author determines the reduction property of the milk in 
the following manner : 

For each sample of milk 10 small tubes are used containing 
1, 2, 3, 4, up to 10 drops of methylene blue solution, respectively. 
Into each tube 5 c. c. of milk is added. After i/4, i/o, 1, 2 hours, 
etc., observations are made as to what extent the milk has been 
reduced. This method, in spite of its apparently greater technique 
is nevertheless quite simple, as the constant watching of the sam- 
ples in order to determine the time is unnecessary. Both time and 
degree are determined. If, for instance, a milk is reduced in three 
hours to tube 8, then the formula will be: E3==8. Good milk 
reduces the first 2 tubes only after 2 to 3 hours ; fresh milk only 
after 10 to 12 hours. 

The Schardinger reduction of formalin methylene blue is of 
no value for the examination of market milk, as it also gives posi- 
tive results with fresh, raw, and boiled spoiled milk. In the same 
way it is not suited for examination of milk from individual cows. 
Miikj'wiiich does not decolorize in a few minutes at 60° C. by the 
Schardinger reagent, consisting of 190 parts water, 5 parts forma- 
lin and 5 parts saturated alcoholic methylene blue solution, may 
be from fresh cows, if the individual sample is taken from the total 
amount of milk of the cow (the first portion of milk at the milking 
does not reduce). 

The "Catalase" test is conducted by mixing together 15 
c. c. of milk and 5 c. c. of 1% peroxide of hydrogen. The mixture 
is placed in a fermentation tube such as is used in the examination 



218 Milk Inspection. 



of wine for the cletermination of sugar, and kept for 2 hours in 
an incubator, and after this period the amount of oxygen formed 
during this time is measured. It should not exceed more than 
about 1 c. c. 

Apparatuses which indicate the total amount of gas formed 
are more suitable; for instance, the "Catalaser" constructed by 
Henkel, or still Ijetter the one by Lobeck, in which a gas collecting 
and measuring tube is so attached above the bulb containing the 
milk that a line gas tube leading from the bulb to the upper part 
of the gas measuring apparatus allows the exit of the oxygen at the 
point. At the bottom of the gas collecting tube another tube 
opens, through which the water contained in the measuring tube 
is displaced by the liberated oxygen. Faitelowitz has constructed 
a shaking apparatus and a special ''Catalaser"; the shaking is 
supposed to expedite the liberation of the oxygen. 

Fresh milk evolves 1 to 2 c. c. of oxygen. Raw or pasteurized 
milk, spoiled through invasion of bacteria, produces considerably 
larger amounts of oxygen ; likewise milk rich in cellular elements 
as a result of physiological or pathological irritations of the udder, 
or mixed milk polluted by such secretions. The test is useless for 
the examination of market milk as to the presence of inflammations 
of the udder. 

High oxygen values of the catalase test in connection with low 
reductase values against the watery methylene blue, create a sus- 
picion of mastitis. 

High values by both methods indicate principally a spoiled 
condition, without differential diagnostic value relative to inflam- 
mation of the udder or bacterial decomposition. If the testing of 
the milk indicates that the product was pasteurized, sterilized or 
otherwise heated, and the catalase test is positive, the generation 
of oxygen proves the spoiled condition of the milk as a result of 
bacterial decomposition. 

AVitli fresh individual samples and samples from individual 
quarters the increased value of catalase proves the presence of 
mastitis, provided that no severe general diseases are present, and 
provided physiological irritating conditions are excluded. If all 
samples from the 4 quarters show increased catalase values, mas- 
titis may be present in all 4 quarters, or there may exist a general 
disease, as for instance tuberculosis or peritonitis. 

The test for amylase is only applicable to raw milk. Into each 
of ten test tubes are placed 10 c. c. of milk and . 1, . 2 up to 1 c. c. 
of a 1% solution of soluble starch which is dissolved through heat- 
ing. The series of tubes are placed for half an hour in the incu- 
bator. Then they are rapidly cooled, and to each is added 1 c. c.^ of 
a solution of iodine and iodide of potassium (1 of iodine, 2 of iodide 
of potassium, 300 of water). If the total amount of starch has 
been converted into sugar, the color of the mixture will be yellow. 
A grayish-yellow with a grayish-blue tinge indicates unchanged 



Fermentation Test. 219 



residues of starch. Generally only tubes 1 and 2 but sometimes 
tube 3 become yellow. 

In the presence of large amounts of amylase, which usually 
runs parallel with the cellular contents, even the other tubes will 
appear yellow. An increased amount of amylase indicates physio- 
logical or pathological irritation of the udder. The raw condition 
of the milk is tested by the determination of peroxyclase. There 
are used either guaiac tinctures, the efficacy of which has been 
tested, or still better mixtures of guaiac-guaiacol with peroxide of 
hydrogen, for instance, resina guaiaci 10.0, guaiacol 10.0, 3% 
perhydrol quantum satis, absolute alcohol 80.0 (Schern). 

Eaw milk becomes blue, heated milk turns yellow. The Eoth- 
enfuss reagent is very reliable and is also recommended on account 
of its keeping qualities. 

First solution : 1 gm. paraphenylendiamin hydrochloride, 15 
c. c. water. 

Second solution: 2 gm. crystallized guaiacol, 135 c. c. 96% 
alcohol. 

After dissolving, both are mixed together which results in a 
white or whitish-yellow reagent. For the execution of the test a 
0.2% solution of peroxide of hydrogen is also essential. The milk 
to be tested is mixed wdth a few drops of a solution of peroxide of 
hydrogen, and then the reagent is added. Eaw milk at once be- 
comes intensely violet, while milk heated to over 80° C. remains 
white. 

The reaction is prettier and more distinct when instead^ of 
milk, milk serum is used, which is prepared in the following 
manner : 

100 c. c. of milk is mixed with 6 to 12 c. c. of lead acetate 
solution, strongly shaken, and filtered through a folded filter. _At 
the plane of contact of the serum with the reagent, a violet ring 
appears if the milk is raw. 

If the reaction does not appear, and the lead-acetate-serum 
becomes turbid through boiling, the milk has been heated above 
80° 0. and probably below the boiling temperature, which however 
was surely reached when on boiling of the serum no more albumen 
is precipitated. 

The fermentation test has less importance for the examination 
of milk to be consumed than of milk to be utilized for the manu- 
facture of cheese. 

The milk is filled into tall, wide test tubes and the latter are 
placed for 24 hours in the incubator at 38-40° C. 

Fresh milk does not curdle after 12 hours ; curdled milk should 
have a pure sour odor and taste, and at the same time a porcelain- 
like, scaly, coagulum with only a few gas bubbles. Many gas bubbles 
and fissures in the coagulum indicate the presence of aerogenes-coli 
and other bacteria which split up the milk sugar with the forma- 
tion of gas. A cheese-like curd develops as a result of the presence 



220 Milk Inspection. 



of rennet producing species of bacteria, which are peptonizing 
bacteria, the presence of which is undesirable in drinking milk. 
Not infrequentl}'' the best milk produces imperfect cnrds. 

Milk from diseased animals curdles more poorly, with the 
formation of an abnormal curd. 

Still less important than the fermentation test is the rennet 
fermentation test which is used in cheese factories, where tlie 
milk, before being placed in the incubator is mixed with a solution 
of rennet. The resulting curd should be elongated and worm- 
shaped, contain few gas bubbles, and should not look twisted or 
pressed flat or swollen. 

The rennet inhibitory test recently recommended by Schern 
accomplishes other purposes than the rennet fermentation test. It 
tests the power of resistance of the milk against the effect of the 
rennet. For the test the following are necessary : 

1. A number of test tubes. 

2. Measuring pipettes of 10 c. c. capacity w^ith i/. c. c. gradua- 
tion and 1 c. c. pipettes divided in tenths and hundredths of 
c. c. graduations. 

3. A water bath or an incubator with a number of perforated 
racks. 

■i. An icebox. 

5. 0.85% solution of common salt. 

6. Solutions of rennet, the values of Mdiich are known and 
which remain constant (standard solutions of a known titer). 

In the performance of the test it is desired to ascertain : 

1. Whether the titer of the solution of rennet still persists 
with sound milk. 

2. Whether the milk to be tested by means of the rennet 
titer does not curdle, or how much more rennet is necessary to 
make the milk curdle. 

The samples are placed for 1 hour in the icebox, and then for 
2 hours in the incubator, whereupon through pouring, a test is 
made as to which dilution of rennet has curdled the milk or 
whether the milk curdles at all up to the limit of titration. 

The test is not applicable to market milk, but only for fresh 
individual samples or samples of milk from individual quarters. 

Milk which utilizes considerably more of the rennet solution 
than the amount which corresponds with its titer is suspected of 
not being normal. 

The test is too laborious for practical control work and does 
not offer any advantages for the recognition of inflammation of 
the udder over the microscopical examination of the centrifugal 
sediment. 

The methods by which the milk is examined for the content of 
complement or amboceptor have the same shortcomings. They 
are of no importance in control work. 

The test for complement is as follows: 



Sedimentation Test. 99]^ 



1. 5% suspension of washed blood corpuscles from guinea 
pigs or rabbits in 0.85% salt solution. 

2. Hemolytic amboceptor of normal blood from cattle or 
goats heated to 56° C. 

3. Milk. 

The milk is placed in tubes arranged in 2 rows of 5 tubes 
each in quantities of 1.0, 0.5, 0.25, 0.1 and 0.0 c. c. respectively. 
One row is inactivated by heating to 56° C. ; then in all the tubes 
the contents are brought up to 1 c. c. by adding salt solution. Fur- 
ther, to each tube are added 0.2 c. c. of the inactivated cattle or 
goat serum- and 0.5 or 1 c. c. of the blood-cell suspension. The 
rack is then placed for 2 hours in the incubator ( shaken frequent- 
ly) and placed over night in the icebox. 

Hemolysis occurs in physiological and pathological irritations 
of the udder. 

The test for amboceptors is carried out in a similar manner, 
with the exception that the milk in all the tubes is inactivated, and 
into the tubes of one row complement is added in quantities deter- 
mined by titration. 

In the test for amboceptor and complement the various sub- 
stances which enter into the test should be controlled for possible 
errors. 

Trommsdorff's method is best adapted to determining the 
quantity of centrifugal sediment in milk. 

The tubes which terminate at the bottom in a graduated capil- 
lary tube (Trommsdorff's tubes) are tilled with "lO c. c. of milk 
and centrifugalized for several minutes in a centrifuge at about 
1500 to 2000 revolutions per minute. All elements having the 
greatest specific gravity collect in the capillary tube. 

All sediment of a yellow, clay or reddish color which does not 
consist of cow manure and which is sharply separated from the 
layer of skimmed milk irrespective of its quantity, should be sus- 
pected as being due to an inflammation of the udder, since larger 
quantities of tissue cells are thrown off only in pathological or 
physiological irritations of the udder. In market milk this test 
gives uncertain results, but in individual samples and in samples 
of individual quarters the results may be well utilized. If the 
centrifugalized sediment is not distinctly separated from the 
skimmed milk, and the scale is therefore not readable, then the tube 
is filled with clear, cool water and the capillary end is turned up- 
ward. The water having a lower specific gravity, penetrates into 
the capillary tube up to the border of the sediment. 

For testing of individual quarters the author recommends the 
sedimentation test in tubes with chisel shaped ends and with 
funnel shaped mouths. The milk is drawn directly into these tubes 
from the quarter, after discarding the first milkl The four sam- 
ples from a cow are allowed to stand for about 8 hours and then 



222 Milk Inspection. 



examined for the presence of sediment. Sediment, which appar- 
ently does not consist of cow manure, indicates an inflannnation of 
the ndder, provided the colostral stage has passed and the animal 
is not close to the end of its lactation period. 

The sedimentation test may be and should be undertaken by 
every dairyman. Its application is easy. Milk which separates 
recognizable quantities of sediment should not be sold or used as 
food for man. 

In the scientific examination of market milk and of individual 
samples, the microscopical study of the milk can no longer be 
neglected. In Munich the sediment of the milk is examined micro- 
scopically. A platinum-wire loop (the wire must be completely 
folded) is passed into the depth of the capillary tubes and without 
turning, the sediment is lifted out by pressing the wire against one 
side and drawing out a loopful. In the procedure the contact of 
the wire with the milk or cream of the tube should be prevented. 
The smear is made in the usual manner; the best way is to place 
the loop of the wire on the slide and by lifting it up a somewhat 
thicker droplet remains at the place of contact. This may be 
spread over the slide and is especially well adajDted for microscop- 
ical examination. 

The smear is dried in the air, fixed by heat or alcohol and 
stained by the ordinary methods. For staining, the author recom- 
mends a thionin solution which consists of y^ concentrated alco- 
holic thionin solution and -/^ distilled water. In market milk are 
observed many plant fibers and plant cells, plant hairs, staph3do- 
cocci united into colonies, colon varieties, acid fast rods, sarcina, 
blackleg and anthrax-like bacteria with or without spores, if the 
milk was produced under dirty conditions. If such a milk sample 
is older, not infrequently mycelial threads germinate from the 
mould spores. If the milk is bad and was transported in dirty 
cans, besides the colon-like bacteria, staphylococci, diplococci, 
streptococci, sarcina, oidia and cheese bacteria may be seen. 

If the milk is at the point of decomposition, diplococci and 
streptococci dominate the field. 

A diagnosis that milk is mixed with the secretion of a cow 
affected with streptococcic mastitis is only permissible, when 
besides the cells from the animal body (leucocytes, epithelia under- 
going fatty degeneration, erythocytes, etc.), the animal forms of 
streptococci are demonstrated. 

The positive finding is decisive but the negative does not 
exclude. Market milk which, besides numerous leucocytes, shows 
no animal streptococci, only creates a suspicion that the secretion 
is from cows with affected udders. 

The increased amount of horny epithelia of the teats in sam- 
ples of individual cows indicates the fresh milking period of the 
animal. 



Table V 




Sediment of dirty market milk which contains the secretions of cows with affected 
udders, and which has been transported in filthy cans. Thionin stain. 1 X 1000. 



Ernst, Milk Bygiene. 



Microscopic Examination. 223 



Tlie presence of epithelial nests from the cistern suggests a 
catarrh of the cistern. 

An increased number of leucocytes and colostral cells indicates 
an irritation of the parenchyma. The causes of the irritations 
are often manifested by the presence of diplococci in phagocytes 
or isolated diplococci and frequently atypical short forms, or the 
typical animal forms of the Streptococcus longus or 8. hrevis are 
recognized. 

Even atypical forms of diplococci and streptococci, when pres- 
ent in such forms in milk only a few hours old, are an indication of 
streptococcic mastitis (care must be exercised in the absence of 
experience and if the evidence is to be used in court). 

In pyobacillosis the typical, short, slender bacilli are found 
which simulate in their morphology the bacilli which frequently 
cover the horny cells of the outside skin of the teats. 

In samples from individual cows, the microscopical examina- 
tion may establish the diagnosis of "tuberculosis of the udder," 
when the specific organisms are found enclosed in leucocytes or 
curds. The staining is carried out with hot carbol-fuchsin solution 
(1 part fuchsin to 10 parts of absolute alcohol, and 90 parts of a 
5% carbolic acid solution). By decolorizing with 33% aqueous 
nitric acid and subsequent washing with alcohol the non-acid fast 
rods and the body cells are decolorized. The decolorized elements 
may be given a blue contrast stain, against the red tubercle bacilli 
by subsequent staining of the preparation with aqueous methylene 
blue or methylene blue anilin water. 

In order to avoid the dragging of too many tubercle bacilli 
into the cream by the cells and fat globules, for the microscopical 
examinations, the milk should be first homogenized. The following 
methods are the simplest : 

a. Knut Arnell recommends mixing 25 c. c. of milk with 2 c. c. 
of concentrated ammonia and 100 c. c. of a mixture of equal parts 
of ether and petroleum ether in a sedimentation cylinder, which 
runs to a point at the bottom and at its lower part is supplied with 
a stopcock. This is frequently shaken and then allowed to stand 
for the separation. The ammonia-casein solution is then drawn 
off, the remaining content is centrifugalized and the sediment 
examined. 

b. Thorner recommends mixing 20 c. c. of milk with 1 c. c. of 
50% potassium hydrate. This is heated in boiling water until in 
complete solution and then centrifugalized. 

c. Biedert recommends adding 10 c. c. of milk to 1000 c. c. of 
Vv^ater containing 4 to 8 drops of sodium hydrate solution. This 
is shaken, boiled and then set away for sedimentation. 

If after staining, the slender rods which remain red are pres- 
ent only in small numbers, or if the sediment shows no cells which 
indicate an inflammation of the udder, or if the examined milk 
proves to be a dirty market milk, then the diagnosis must be estab- 



224 Milk Inspection. 



lislied by incubation, since the milk may contain from the feed, etc., 
only harmless, acid fast rods. 

The inoculation is made into guinea pigs by injecting- them 
either subcutaneously or intramuscularly in the hind leg with either 
1 c. c. of the full milk, or better, with the centrifugal sediment mixed 
with a snuill amount of the skimmed milk with or without cream. 
The sediment should be obtained by using rapidly revolving elec- 
tric centrifuges. 

If the samples have to be transported long distances, they 
should be mixed before transportation, and if possible immediately 
after drawing the milk, with 1:2000 to 1:3000 of formalin (boric 
acid 1 :50 or 1 :100 is also satisfactory). The tubercle bacilli which 
are protected by a waxy capsule from the effects of the preserving- 
agents, are not harmed b}^ such preservation to such an extent that 
they could no longer be demonstrated b}' inoculations. 

For each milk injection at least two guinea pigs should be 
used, since occasionally the inoculated animals die as a result of 
some other intercurrent disease. 

In the presence of tubercle bacilli the regional lymph glands 
swell after several days or a few weeks. Such animals, 
if they do not die before, should be killed on the appearance of 
these swellings, and they as w^ell as those which died should be 
examined for the presence of tuberculosis. The surviving guinea 
pigs should be kept under observation for several months. 

In examining entire herds, it is advisable to group the cows; 
for instance, five animals may form one group and the mixed milk 
of this group should be separately inoculated. 

The counting of bacteria is carried out either by the ordinary 
method of plating- which is made with certain dilutions of milk on 
agar or gelatin or also by direct counting in smears which should 
be prepared according to Olav Skar. 

The method consists in mixing in a reagent glass 4/10 c. c. of a 
2% solution of carbol-methylene blue (for animal cells and bac- 
teria) and 3.5 c. c. carbol-methylene blue, with 0.5 c. c. of a S% 
sodium hydrate solution (for bacteria alone). Then 10 c. c. of milk 
is added to the stain with a pipette and heated for about 10 minutes 
at 70° C. Of the mixture, 1/50 of a c. c. is uniformly smeared 
upon a certain sized field (24 X 20 m. m.) of a special slide, and 
dried in the air. AVithout any further fixation or other treatment, a 
number of fields in the smear are counted in their entire length and 
width, and with the aid of the ocular micrometer the number of 
bacteria in the counted fields is calculated to the c. c. of milk, ac- 
cording to the standard given below. When chains and clumps are 
encountered each bacillus must be counted. The ocular micrometer 
of Zeiss in Jena as applied by Skar has a determined field capacity 
so that one bacterium, with the above technique and with a certain 
tube length of the microscopCj viewed with a 1/12 oil immersion 



Coimtina;- Bacteria. 225 



objective, indicates the following number of bacteria for the 

various fields which are designated by letters : 

In 1^ of square a = 40,000,000 per c. c. of milk 
In 1/2 of square a = 20,000,000 per c. c. of milk 
In total square a = 10,000,000 per c. c. of milk 
In 1/4 of square b = 8,000,000 per c. c. of milk 
In 1/0 of square b = 4,000,000 per c. c. of milk 
In total square b = 2,000,000 per c. c. of milk 

In circle c = 1,000,000 per c. c. of milk 

In total field of 

observation = 800,000 per c. c. of milk 

The total number of bacteria found in all the counted fields 
is multiplied by the relative number corresponding to the field of 
the size that was counted and divided by the number of counted 
fields. If, for instance, in 20 ocular fields of size "a" Skar found 
the number to be 150 bacteria, then these figures give : 

150X10,000,000 ^150x500,000=75,000,000 per c. c. of milk. 

Skar always found many more bacteria by this method than 
were found by the plate method (2 to 70 times as many). 

The direct counting is more rapid and more accurate than 
the plate counting method. 

As already mentioned, for practical control work the counting 
of bacteria may be omitted. In this work the reductase test offers 
a quicker determination of the spoiled condition of the milk. 

For special examinations the following methods are recom- 
mended: For determining age and decomposition the reductase 
test and periodically repeated acid tests, besides the microscopical 
examination of the sediment, should be applied. 

For determining decomposition of pasteurized milk, the per- 
oxydase test, in combination with the reductase test, and, at times 
also the catalase test and microscopic examination of the sediment, 
should be used. 

For the judgment of dirty milk, the determination and esti- 
mation of the dirt content, the reductase test, periodical acid test 
and microscopic examination of the sediment should be made. 

Inflammation of the Udder. 

(a) Market milk: 

1. Determination of the quantity and appearance of 

the centrifugal slime. 

2. Microscopic examination of the sediment _ for 

parenchyma cells and the presence of animal 
forms of streptococci. 
3. In tuberculosis: Inoculate. 

(b) Individual samples: 

1. Trommsdorff test. 

15 



226 ^lilk Inspection. 



2. Microscopical test of the sediment and examina- 

tion as to the presence of parenchyma cells and 
diplococci, streptococci of the short and long 
forms, particularly the animal types or the 
pyogenes or tubercnlosis bacillus. 

3. If necessary the catalase test or examination for 

amylase. 

(c) Samples from individual quarters: 

1. Trommsdorff or sediment tests. 

2. Microscopy and, if necessarj^ inoculation. 

3. Catalase or amylase test. 

In examinations for milk defects, the following tests are 
reconnnended : 

1. Tests with the senses. 

2. Shaking test (soapy milk). 

3. Eeductase test (frequently the reduction appears very 

slowly, for instance, with tallowy and soapy milk). 

4. Acid tests. 

5. Historical consideration of the conditions of stables, 

pasturage, litter, feed and water, preparation of milk. 

6. Fermentation test. 

7. Cultivation of bacteria from the milk, feed, pastures, etc., 

at temperatures at which the defects in the milk 
appeared. 

8. Examination of cultures in sterilized milk. 

(a) Pure cultures, 

(b) Special mixtures of colonies. 

The veterinarian should also be able to conduct the routine 
examination methods usually conducted in the milk laboratory 
and the preliminary chemical tests for adulteration, provided food 
chemists are not available in such localities. It would lead too 
far to mention at this time all the methods which may be applied 
in suspected adulterations. Only a few methods will be described, 
particularly those which are employed at the official milk labora- 
tory in Munich. 

Determination of the specific gravity of milk. It is best to 
test the milk for its specific gravity after heating it to 15° C. or 
in the neighborhood of this temperature. The milk is shaken 
up and it is advisable to make the test in suspended cylinders with 
the aid of an aerometer and a thermometer. It is not advisable 
to use aerometers into which thermometers are fused. The lac- 
todensimeter used for milk must be officially tested. The specific 
gravity of milk varies in accordance with its contents in dis- 
solved, suspended and emulsified ingredients. 

The lactodensimeter is slowly immersed in the milk and 
should not touch the walls of the cylinder. After the instrument 
has come to a rest, the place at which the level of the fluid touches 



Specific Gravity. 227 



the lactodensimeter is read. The numbers on the lactodensmieter 
indicate the second, third and fourth decimals of tlie specific 
gravity. For each additional degree above 15° C, 0.2 should be 
added to the reading of the lactodensimeter, and for each degree 
below 15° C, 0.2 should be deducted. In this way the corrected 
readings of the lactodensimeter are obtained, before which must 
be placed 1.0 in order to obtain the specific gravity. The Munich 
lactodensimeter which is adjusted to a temperature of 15° C. is 
recommended for general use. 

The specific gravity of the milk may also be determined by 
the so-called pyknometer. This method is suitable for small 
quantities of milk. A third method of determination of the specific 
gravity is Westphal's modification of Mohr's balance. This is so 
constructed that the lever arm of the balance from its zero point 
(the axis of the balance) is provided with 9 notches at such dis- 
tances, that a rider suspended on it indicates from 1 to 10 times 
its weight, depending upon whether it is pushed towards the 
end of the arm or towards its axis. Point 10 at the end of the 
arm is provided with a loop. A weight A, suspended in the loop 
of point 1, acts on point 1 only as a weight of A/10 at point 10. 

The weights A, Ai, and A2, may be mutually interchanged and 
indicate the integer and the first decimal figure of the specific 
gravity, depending upon whether they are suspended in the loop 
or in the notches. The weight B=l/10 of A, and indicates when 
in the notches 1/100, while C represents 1/10 of B and when in 
the notches indicates the 1/1000 of the specific gravity. 

^ By shifting the weight C between two notches the fourth 
decimal point may also be approximately established. 

Hydrometers made of glass and the use of separate ther- 
mometers are recommended. 

The specific gravity of market milk varies between 1,029 to 
about 1,033. 

The increased or decreased specific gravity, as compared with 
the average specific gravity of the milk of the respective locality, 
can at the most only be suspected as being caused by dilution with 
water or by removal of the cream. In case of double adulteration 
the specific gravity may remain normal. 

After the specific gravity has been determined, the fat content 
is established by one of the ordinary empiric methods. Gerber's 
acidbutyrometric method is employed at the milk control station 
of Munich. 

The following apparatus is needed for this method. 

1. Centrifuge. 

2. Butyrometer (round butyrometer, flat butyrometer, 
** optical" butyrometer) which is a milk receptacle, ending in a 
graduated tube into which are poured sulphuric acid, amyl alcohol 
and milk, and which is closed by means of a rubber stopper. 

3. A 10 c. c. pipette or an automatic measure adjusted for 



OOQ Milk Inspection. 



10 c. c, for measuring the sulphuric acid, an 11 c. c. pipette for 
milk and a 1 c. c. pipette or a corresponding automatic measure 
for amvl alcohol. 

4. ' Commercial sulphuric acid of a specific gravity of 1,820 
to 1,825 (at 15° C.)- 

5. Amyl alcohol with a specific gravitv of about 0.815 (at' 
15° C.) and a boiling point of 128 to 130° C. 

6. Shaking a))i)aratus with a protective cover. 

7. Water bath. 

First sulphuric acid (10 c. c.) is poured into the butyrometer, 
then 11 c. c. of milk, and finally 1 c. c. of amyl alcohol. The tube 
is closed with a rubl)er stopper and then roughly shaken. Through 
mixing, the contents become greatly heated. After the disappear- 
ance of all flakes and after the tube has been held for several 
minutes at 65° C, it is centrifugalized. Following the centrifu- 
galization it is again heated at 65° C. and then quickly read. 

In order to avoid the more, or less dangerous handling of 
sulphuric acid, Sichler's "sinacid" and Gerber's "sal" methods 
have recently been inaugurated, in which alkaline salt solutions 
are employed instead of the sulphuric acid. The results are ap- 
proximately the same as in the acid butyrometers. 

[In the United States the most popular method for determin- 
ing the amount of fat in milk is by the Babcock test. If carefully 
applied the results can be relied upon without question. 

In the application of this test sulphuric acid is used to free 
the fat globules by dissolving the casein. Then by proper cen- 
trifuging the fat is collected in such a manner that it may be 
readily measured. 

For the execution of the test special test bottles are provided. 
A definite amount of milk (17.6 c. c.) is placed into a test-bottle 
to which 17.5 c. c. of commercial sulphuric acid of a specific gravity 
of 1.82 to 1.85 is added by means of a pipette, burette or other 
measuring apparatus. The contents are then thoroughly and 
carefully mixed, as a result of which the fluid turns brown and 
becomes somewhat heated. The bottles are then placed into a 
centrifuge which is specially constructed for this purpose, and 
centrifuged for 5 minutes at 900 to 1,200 revolutions per minute. 
After removing the bottles from the centrifuge they are filled with 
hot water up to the lower part of the neck and they are again 
centrifuged for two minutes. A sufficient amount of hot water 
is now added to float the melted fat into the neck of the bottle 
which is provided with a graduated scale, and the centrifuging 
is repeated for one minute. The volume of fat can be easily read 
from the graduated portion of the bottle, and this reading should 
be done while the neck of the bottle is still hot. — Trans.] 

The fat content of the milk fluctuates between wide limits. 
The total solids and the fat-free solids may be established with 



Calculation of Milk Solids. 229 

the aid of the specific gravity and the obtained fat content. 

d^percentage of solids^i/o X f + 2.665 X — " In this 

equation f==fat content and s=specific gravity. 

Fleischmann has prepared two tables for the values of y2Xf 

and for the value of 2,665 X — ' for the specific gravity 

s 

from 1,028 to 1,0369 and for 2.5% to 5.49% of fat, so that through 
simple addition of the determined values, the respective content 
of solids can be established. 

Still simpler is the calculation of the solids by Ackermann's 
''slicle-ruler," which consists of two disks united at the -turning 
point and which slide against each other. The larger of these 
contains the numbers for the solids and fat contents, while the 
smaller has the numbers for the specific gravity. By turning the 
small disk the established specific gravity number and the fat con- 
tent number of the tested sample are placed opposite each other. 
An indicator fastened to the inside disk points to the amount of 
the total solids. 

The amount of fat-free solids is obtained by subtracting the 
percentage of fat from the percentage of total solids. This is an 
important factor in suspected cases of adulteration. Marked dif- 
ferences are the result of artificial influences but in individual 
samples the difference may be due to natural fluctuations. 

Milk with a high fat content has as a rule more fat-free solids. 
The milk of cows of the highlands has more fat-free solids than 
the milk of cows from the lowlands. 

According to Fleischmann, it should be noted that the fluctua- 
tions of the different values indicated herein, vary in the different 
milking periods as compared with the annual average. These 
fluctuations may amount to : 

10% in the lactodensimeter reading (specific gravity). 

30% in the fat content. 

14% in the total solids. 

10% in the fat-free solids. 
According to Fleischmann, the fat-free solids do not fall below 
7.9%, and the specific gravity of the total solid matter (m) which 
may be determined by the following formula : 

_ s X d 

^~ s X d— 100 s + 100 

exceeds only exceptionally 1.4 and is usually 1.31 to 1.36. 

Excepting the milk of individual cows or that of a few cows, 
according to the agreement of German food chemists, the presence 
of adulteration is established as follows : 

1. Adulteration with water when the specific gravity of the 



230 ^^''1^ liispc'C'tiou. 



milk is below 1.028, that of the serum ))elo\v 1.026 and the content 
of fat-free solids falls considerably below 8%. 

2. Cream has been removed from the milk when in the pres- 
ence of an increased specific gravity of the milk and normal specific 
gravity of the serum or normal content of fat-free solids, the per- 
centag'e of fat content of the milk solids falls considerably below 
20% ; that is, the speeilic gravity of the latter is increased consider- 
ably above 1.4, 

3. Adulteration with water together with removal of some 
of the cream may be suspected when with a normal specific gravity 
of the milk, that of the serum falls below 1.026, and with a dimin- 
ished amount of all the ingredients of the milk the fat content of 
the solids falls considerably below 20% ; that is, the specific gravity 
of the latter is increased considerably over 1.4. The percentage 
of fat contents of the solids is obtained from the following formula : 

f X 100. 
d 

At the same time it must be remembered that no definite 
figures of limitation should exist and that only comparative figures 
are convincing. The sample for comparative tests may be ob- 
tained by informing the manager of the dairy or the responsible 
producer that the milk is suspected of being watered, and he is 
directed to devote special attention to the milk production and its 
subsequent handling. If following this procedure the milk becomes 
notably changed the test may be considered as comparative, pro- 
vided that it is not preferred to undertake immediately an official 
comparative test. This must be done as quickly as possible, and 
not later than the third day after the suspicion has been estab- 
lished. According to Herz the following formulas apply in the 
calculation of adulterations : 

w = the added water contained in 100 parts of milk. 

V = the added water to 100 parts of milk. 

p = the fat removed from 100 parts of milk. 

ri = the fat-free solids of the stable sample. 

ro = the fat-free solids of the suspected market sample. 

f, = fat contents of the stable sample. 

fo = fat contents of the suspected market sample. 

M = 100 — w, the amount of original undiluted milk contained 
in 100 parts of watered milk. 

100 X (r, — r,) 



w 



100 X (r, — r,) 



p =. f,— f, + 



1*2 

f. X (f>— f^) 



100 



Detection of Adulteration. 231 



Finally in combined adulteration we have 



^100 ^ J X 


rf _M X f, — 100 f.l 
L M J 



P — fi- 100 

other formulas according to Vogel are : 
The addition of water in per cent 

= 1^ X 100 — 100 

The removed amount of fat in per cent 

= 100 X ^ — " 

±1 

or according to Bohmlander : 

V ^ — X w — W, in which w = the contents of water in the 
r2 

suspected sample and W = the contents of water of the 
unsuspected sample, and 



E = 100 I 1— 



i^-m) 



(E = removed fat in % of the fat content) 

The establishment of the suspicion and the establishment of 
the amount of adulteration are greatly supported by the examina- 
tion of the milk serum free from proteins, which contains the sub- 
stances dissolved in the milk, the content of which is subject to 
only the slightest variations. The examination is carried out 

1. Through the specific gravity, or 

2. Through refractometric observations. 

It is best to prepare the serum according to Ackermann by the 
addition of . 25 c. c. of a solution of calcium chloride of a specific 
gravity of 1 . 1375, to 30 c. c. of milk, which mixture is thoroughly 
shaken in a reagent tube. The tube is closed with a rubber stopper 
through which a glass tube is inserted as a reflux condenser, 
and it is then heated to boiling for 15 minutes. The tubes are 
then rinsed in cold water and the condensation water of the cool- 
ing tube is united with the serum by slow, repeated and careful 
shaking. With milk which is in a state of decomposition, the milk 
serum turns cloudy and the values of refraction are also changed. 
Milk from affected udders which is considerably changed, fre- 
quently curdles only following the addition of double quantities 
of calcium chloride solution. Differences in the refraction values 
of 2.4 to 2.50 indicate about a 10% adulteration. The removal 
of cream does not change the refraction value of the milk. 

For refraction the serum prepared according to Ackermann 
does not have to be filtered, but this should be done for the deter- 



Milk Inspection. 



iiiination of the specific gravity, which is usually 1.026 to 1.027. 
In applying this method it may become necessary to use larger 
amounts of serum. Differences of about 0.0025 in the specific 
gravity indicate mixing with about 10% of water. 

The positive demonstration of nitrates in milk is always a 
proof that the milk has been watered and with water that should 
be considered as objectionable as drinking water, or that has been 
used for the rinsing of the milk containers, and wliich according 
to its quality must be considered as impure. Milk which gives the 
nitrate reaction should therefore be considered not only as adul- 
terated but also as being spoiled in the sense of the pure food 
law and even as injurious to health. The nitrate test may become 
of great importance for the conviction of certain persons, when 
for instance the water of the well at the barn contains nitrates, 
while the one at the farmhouse has no nitrates and vice versa. 
According to Rothenfusser the nitrate test is a su1)stantiating 
proof of great importance. Milk samples contaminated with 
manure and litter do not give the nitrate test. 

Nitrates and nitrites do not occur in milk of animals fed and 
cared for in the usual manner on the farm. Rothenfusser ascer- 
tained that the unavoidable residue of water used in rinsing the 
milk containers represents only a tenth or a twentieth part of the 
amount of water, which is necessary to make a 1% addition and 
that the residue of water retained in the rinsed vessel must possess 
the qualities of ditch water in order to be capable of adding to 
the milk a demonstrable amount of nitrates. According to Rothen- 
fusser the test may be carried out to the best advantage, by placing 
into small, flat, white porcelain vessels 2 c. c. of pure sulphuric 
acid of a specific gravity of 1.84, over which a small amount of 
crystallized diphenylamin is sprinkled from a sprinkling cylinder 
(a reagent tube with, a perforated cork stopper, into which a short 
glass tube of about 3 mm. inside diameter is inserted). 

Then a small quantity of chloride of calcium serum of the 
milk to be examined is allowed to flow in from the edges of the 
vessel. The appearance of the grayish-blue clouds and stripes in 
the fluid indicates the presence of nitric acid in the milk. 



Chapter XI. 

FUNDAMENTAL PRINCIPLES OF LEGISLATIVE 
MILK CONTROL. 

The practical inaiigiiration of milk hygiene is, of course, only 
possible where proper laws and ordinances are at our command 
for the accomplishment of the result. The laws, regulations and 
ordinances of the various states and municipalities promulgated 
for the purpose of controlling the milk supply lack uniformity in 
many of their essential requirements, and it is apparent that these 
measures were drafted to meet the conditions prevailing in the 
different localities. Furthermore, a general federal control of the 
milk supply cannot be considered practicable, except possibly in 
so far as interstate shipments of milk may be involved. 

The individual states may foster the interests of public health 
by the inauguration of such legislative measures as will assure a 
wholesome and clean milk supply for the different municipalities 
within the state, particularly when the necessity prevails for the 
shipment of milk from long distances to a city. For this purpose 
the state might well be divided into districts, supervised by com- 
petent inspectors who would primarily inspect the cattle and 
stables, the methods of producing the milk and its transportation. 
Such inspectors could also be of splendid service in the control 
and possible eradication of contagious diseases which not only 
may have an effect on milk production, but which are also of im- 
portance to animal industry in general. 

The largest proportion of actual control work, however, will 
have to be carried out by the different municipalities, where, with 
proper ordinances and with competent inspectors and laboratory 
officials, an efficient control could be maintained which would assure 
a wholesome milk supply to the consumers. It is apparent that 
such ordinances must be drafted to meet the local conditions, which 
would depend upon the dairying industry in that section, the num- 
ber of the population and the feelings of the people. 

While there exists no uniformity in the regulations govern- 
ing milk inspection and milk hygiene in general in the different 
parts of the United States, the necessity for at least a uniform 
standard has been met in a most satisfactory manner. After con- 
siderable agitation medical milk commissions were organized in 

233 



o*^^ Principles of Leoislative l\rilk roiihol. 



varioiTS cities of the United States for the purpose of estahlishino- 
milk standards and also of ohtainini^- such legislation as would 
assure clean and wholesome milk to the connnunities. The orgaui- 
zation of milk connnissions in this country was undoubtedly an 
important step towards the improvement of the quality of milk, 
and only by the concerted work of these and similar organizations 
can the country at large l)e assured of a proper milk supply. It 
is regrett-cible that milk, the most important food, is not considered 
by the laity of sufficient importance to l)e subjected to the most 
rigid control, especially since it constitutes the principal, and in 
early life the only food of children. 

The second report of the Commission on Milk Standards, ap- 
pointed by the New York Milk Committee, embodies the principles 
for a wholesome milk supply and would serve well as a basis for 
the formulation of effective ordinances. Therefore it is deemed 
advisable to reproduce these principles from the Public Health 
Eeports of August 22, 1913, United States Public Health Service. 

Need of Milk Control. 

Proper milk standards, while they are essential to efficient 
milk control by public health authorities and have as their object 
the protection of the milk consumer, are also necessary for the 
ultimate well-being of the milk industry itself. Public confidence 
is an asset of the highest value in the milk business. The milk 
producer is interested in proper standards for milk, since these 
contribute to the control of bovine tuberculosis and other cattle 
diseases and distinguish between the good producer and the bad 
producer. The milk dealer is immediately classified by milk 
standards, either into a seller of first-class milk or a seller of 
second-class milk, and such distinction gives to the seller of first- 
class milk the commercial rewards which he deserves, while it 
inflicts just penalties on the seller of second-class milk. For milk 
consumers, the setting of definite standards accompanied by proper 
labeling makes it possible to know the character of the milk which 
is purchased and to distinguish good milk from 1iad milk. In the 
matter of public health administration, standards are absolutely 
necessary to furnish definitions around which the rules and regula- 
tions of city health departments can be drawn, and the milk supply 
efficiently controlled. 

Public Health Authorities. 

Wliile public health authorities must necessarily see that the 
source of supply and the chemical composition should correspond 
with established definitions of milk as a food, their most important 
duty is to prevent the transmission of disease through milk. This 
means the control of infantile diarrhea, typhoid fever, tuberculosis, 



Disease Transmitted Through Milk. 235 

diphtheria, scarlet fever, septic throat infections, and other infec- 
tious diseases in so far as they are carried by milk. 

Septic Sore Throat. 

Septic sore throat deserves special mention because of the 
frequency in recent years with which outbreaks of this disease 
have been traced to milk supplies. The suggestion has been made 
that the infection of the milk is due to udder infection of the cow 
and on the other hand it has been suggested that it is due to con- 
tact with infected persons. The uncertainty can not be dispelled 
until cases of septic sore throat are regularly reported and tabu- 
lated by public health authorities. The commission therefore rec- 
ommends that public health authorities make septic sore throat 
a reportable disease. 

Economic Problem. 

The commission recognizes the magnitude of the milk industry, 
and that the improvement of milk supplies is primarily an eco- 
nomic problem. The success achieved by the experiment in milk 
production, which has been carried out on a very large scale by 
the New York Dairy Demonstration Co., is an illustration of the 
fact that an extra price or premium paid to the producer for 
cleanliness and care will bring results far more quickly and 
certainly than instructions or official inspection. But while the 
basic problem is economic, and must eventually be solved by com- 
merce, public health authorities must show the way and must estab- 
lish standards and regulations in the interest of consumers, the 
value of which even the consumers themselves often fail to ap- 
preciate. 

Legal Requirements. 

A prime requisite of effectiveness is that local milk laws shall 
not exceed sanitary limitations. The commission has not entered 
into a discussion of fimdamental state laws, but it recommends 
that state laws be amended wherever necessary in order that every 
municipality may have the legal right to adopt whatever ordinances 
it sees fit for the improvement of the milk supply. The commission 
advocates that local health laws be carefully drawn Avitli regard 
to their legality under the general laws of the localities to which 
they apply, since a decision against a milk law in one locality is 
liable to be used as a precedent against milk laws elsewhere. 

Standard Rules and Regulations. 

The commission has drawn up a set of standard rules and 
regulations for the control of milk. These are the result of a study 
of the printed rules and regulations of the cities of the United 
States and of foreign countries and represent an immense amount 



o;](^ Principles of Legislative Milk Control. 

of work on the part of the special committee of the commission 
to wliich the task was assii>ned. Some communities are in a posi- 
tion to adojit all of these rules and reunlations at the present time, 
while other connnniiities will be obliged to adopt a few rules at a 
time as public sentiment and local conditions warrant. It is real- 
ized that some of the rules may have to be modified to meet local 
eouditious. It seems wise to the commission to divide the regula- 
tions into two parts: First, requirements, under which head are 
set down those provisions which are so fundamentally necessary 
that no community is justified in compromising* on them ; second, 
reconnnendations, under which head are set down provisions which 
are necessary for a good milk supply, but on which there can be 
a certain amount of latitude for compromise by those communi- 
ties in which public sentiment is not ready to support more than 
a moderate degree of protection of human life. 

Administrative Equipment. 

Another prime requisite is that the administrative depart- 
ments shall be adequately equipped with men, money, and labora- 
tory facilities. In smaller communities cooperation between local 
boards of health to the extent of exchanging reports would elimi- 
nate much duplication. Where a community can not maintain a 
laboratory it can enter into laboratory arrangements with other 
communities, and several can combine in the use of a common 
laboratory. Much of the expense of tuberculin testing can be 
borne 1)y the national and state governments. The commission 
is of the opinion that results can not be expected from laws where 
there is not sufficient appropriation and where there is no ma- 
chinery for their enforcement. On this subject the commission 
passed a resolution as follows : 

Whereas the appropriations g^enerally made for the purposes of carrying on 
laboratory analyses of milk are now in most eases entirely inadequate: Therefore be it 

liC-'ioli-cd, That this commission recommends for the consideration of the authorities 
concerned an appropriation of funds commensurate with the importance of lalioratory 
methods, which are of paramount importance in the hygienic control of the milk supply. 

Grading of Milk. 

There is no escape from the conclusion that milk must be graded 
and sold on grade, just as wheat, corn, cotton, beef, and other 
products are graded. The milk merchant must judge of the food 
value and also of the sanitary character of the commodity in which 
he deals. The high-grade product must get a better price than at 
present. The low-grade product must bring less. In separating 
milk into grades and classes the commission has endeavored to 
make its classification as simple as possible and at the same time 
to distinguish between milks which are essentially different in 
sanitarv character. 



Pasteurization of Milk. 237 



In general two great classes of milk are recognized, namely, 
raw milk and pasteurized milk. Under these general classes there 
are different grades, as indicated in the report of the committee 
on classification. 

Pasteurization. 

While the process of pasteurization is a matter which has at- 
tracted a great deal of attention in recent years, the commission 
has not entered into any discussion of its merits or demerits, but 
has given it recognition in its classification as a process necessary 
for the treatment of milk which is not otherwise protected against 
infection. 

The commission thinks that pasteurization is necessary for all 
milk at all times, excepting grade A, raw milk. The majority of 
the commissioners voted in favor of the pasteurization of all milk, 
including grade A, raw milk. Since this was not unanimous the 
commission recommends that the pasteurization of grade A, raw 
milk, be optional. 

The process of pasteurization should be under official super- 
vision. The supervision should consist of a personal inspection 
by the milk inspector. The inspections shall be as frequent as 
possible. Automatic temperature regulators and recording ther- 
mometers should be required and the efficiency of the process 
frequently determined by laboratory testing. 

Pasteurizing Temperatures. 

The destruction of the chemical constituents of milk by heat 
occurs at higher temperatures than those necessary for the destruc- 
tion of the bacteria of infectious diseases transmissible by milk. 

The commission passed a resolution regarding the temperature 
of pasteurization as follows : 

That pasteurization of milk should be between the limits of 140° F. and 155° F. At 
140° F. the minimum exposure should be 20 minutes. For every degree above 140° F. the 
time may be reduced by 1 minute. In no case should the exposure be for less than 5 
minutes. 

In order to allow a margin of safety under commercial condi- 
tions the commission recommends that the minimum temperature 
during the period of holding should be made 145° F. and the hold- 
ing time 30 minutes. Pasteurization in bulk when properly carried 
out has proven satisfactory, but pasteurization in the final con- 
tainer is preferable. 

It is the sense of the commission that pasteurization in the 
final container should be encouraged. 



238 Principles of Legislative Milk Control. 



Labeling and Dating of Milk. 

The commission voted that all milk should be labeled and 
marked with the grade in which it is to be sold. In dating- milk 
nniform methods shonld be adopted for all grades of both raw 
milk and pastenrized milk, both nsing the day of the week or both 
nsing the day of the month. All milk shonld be dated nniformly 
with the date of delivery to the consumer. Raw milk should not 
be dated with the date of production, while pasteurized milk is 
dated with the date of pasteurization, since this places certified 
milk at a disadvantage 1)y making it possible for pasteurized milk 
of a lower grade to carry a later date. The stamping on the label 
of the day of the week is sufficient for dating. 

Bacteria. 

The subject of bacteria in milk received more attention than 
any other matter brought before the commission. The commission 
recognizes that bacteria in milk in the majority of instances indicate 
dirt, or lack of refrigeration, or age, while in the minority of 
instances the bacteria of disease may be present. The routine 
laboratory methods for examining milk have as their purpose only 
the control over dirt, refrigeration, and age, and it is a rare thing 
for a laboratory to undertake the examination of milk for the 
bacteria of disease because of the extreme difficulties in detecting 
them. The more efficacious method of protecting milk from infec- 
tion by the bacteria of human contagion is by medical, veterinary, 
and sanitary inspection, and by pasteurization. Milk with a high 
bacteria count is not necessarily harmful, but when used as a food, 
particularly for children, is a hazard too great to be warranted. 
Milk with a high bacteria count, therefore, should be condemned. 
Milks wdtli small numbers of bacteria are presumed to be whole- 
some, unless there is reasonable ground for suspecting that they 
have been exposed to contagion. 

Bacterial Standards. 

The commission recognizes the difficulty in interpreting 
bacteria counts. At times misleading conclusions have been drawn 
from such counts. In establishing the bacterial standards for a 
city it is always necessary to take into consideration the necessary 
age of the milk and in lesser measure the distance hauled and 
methods employed in its hauling. It will always be possible for 
a community which consumes milk produced on its own premises, 
or within 12 hours of its production, to insist upon and maintain 
a lower bacterial standard than can one where the milk is hauled 



Bacterial Standards. • 239 



many miles into town in a wagon, to be consumed within 24 hours 
after it is produced. In like manner this second type of city can 
always maintain a lower bacterial standard than a city where the 
general milk supply is hauled by railroad long distances and is 
several days old when consumed. In drawing conclusions as to 
the relative efficacy of milk control in cities comparisons must be 
made between cities of the same class. 

The commission deems it ot the utmost importance that some 
standard method should be adopted for estimating and comparing 
the bacterial character of milks, since by this means only is it 
possible to grade and classify milks and to enforce bacterial 
standards. There is much diversity of opinion as to the best 
method of valuing bacteria counts. The average of a series gives 
results which are misleading about as frequently as otherwise. In 
the average a single high figure may unduly overbalance a large 
number of exceedingly low counts. There are objections to the 
use of the ''median" or middle number when the counts are ar- 
ranged in order of size, for the reason that the middle figure does 
not distinguish between two groups in one of which there may be 
some very high counts above the median and in the other of which 
there are none. The method of dividing results into groups as 
recommended by the American Public Health Association, while 
a step in the right direction, is cumbersome and does not clearly 
indicate whether or not a milk conforms to a given bacterial 
standard. 

The commission passed a resolution at its last meeting regard- 
ing the number of bacterial tests necessary to determine the grade 
into which a milk falls, as follows : 

That the grade into which a milk falls shall be determined baeteriologically by at 
least five consecutive bacteria counts taken over a period of not less than one week nor 
more than one month, and at least 80 per cent (four out of five) must fall below the limit 
set for the grade for which the classification is desired. 

Laboratory Examinations for Bacteria. 

On the subject of laboratory examinations of milk for bacteria 
the commission passed the following resolutions : 

1. That the interests of public health demand that the control of milk supplies, 
both as to production and distribution, shall include regular laboratory examinations of 
milk by bacteriological methods. 

2. That among present available routine laboratory methods for determining the 
sanitary quality of milk the bacteria count occupies first place. 

3. That bacteriological standards should be a factor in classifying or grading milks 
of different degrees of excellence. 

4. That in determining the grade or class of a raw milk the specimen taken for 
bacteriological examination should be of milk as offered for sale. 

5. That there should be bacteriological standards for pasteurized milk which should 
require laboratory examination of samples immediately before pasteurization as well as 
of milk ofPered for sale. 

6. That the bacteria count of milk indicates its quality and history as it is modified 
by contamination, handling, dirt, temperature, or age. A high, count indicates the 
necessity of investigation and inspection. 



240 Principles of Legislative Milk Control. 



7. That there be ailopted as standards for making the bacteria count the standard 
methods of the American I'nhlic Health Association, laboratory section, recommending, 
however, the following aniendiiionts: 

A. That the culture nu^dium used for testing milk be identical in its composition 
and reaction with the culture medium used for the testing of water provided in the 
standard methods of water analyses of the American Public Health Association. 

B. That incubation of plate cultures be made at 37° C. for -iS hours. 

The bacterial standards given in the report are the work of a 
special committee of bacteriologists who considered all of the bac- 
terial standards now in nse. It is believed that the standards 
suggested are fair and wise and give full consideration to the 
state of the industry and of public health control. The commission 
l)elieves that the adoption and enforcement of these bacterial 
standards will be more effective thari any other one thing in im- 
proving- the sanitary character of pnl)lic milk supplies. The en- 
forcement of these standards can he carried out only by the 
roguhir and frequent laboratory examinations of milks for the 
numbers of bacteria they may contain. 

Chemical Standards. 

The chemical standards suggested are the work of a special 
committee, composed of chemists, which has carefully considered 
the natural composition of milk and the Federal and State stand- 
ards already established. The standard of 3.25 per cent fat and 
8.5 per cent solids, not fat, here proposed is in accordance with 
the recommendations of the Association of Official Agricultural 
Chemists and has been adopted by the United States Department 
of Agriculture and by a larger number of States than has any 
other standard. The simplification of the Babcock test makes the 
determination of fats and solids not fat an easy procedure quickly 
applied. Such chemical examinations of milk can be readily 
adopted and executed by any health-board laboratory at a very 
moderate expense. It is believed that such chemical standards as 
are suggested will inflict no real hardship on the milk producers 
of this country and that the provision regarding substandard 
milks is a liberal one. 

Microscopic Examination of Milk. 

Because of studies which have been made during the past year 
the commission thinks it wise to omit temporarily any definite 
statement on the subject of microscopical examination of milk, and 
the determination of pus and bacteria by sedimentation methods, 
nntil further studies have been made. A special subcommittee has 
been appointed for this purpose which will make studies during 
the present year and the commission will take action on this matter 
at one of its later meetings. 



Labeling' and Grading Milk. 241 

Mislabeling. 

The commission resolved that the sale of milk which is mis- 
labeled or misbranded shall be punished by suitable penalties. 

Publicity. 

The commission fully considered the matter of the publication 
of laboratory examinations of milk by city and town health authori- 
ties. When proper standards and regulations are established and 
adequate facilities furnished for laboratory work, it is believed 
that the laboratory tests will give an index of the character of 
the milk delivered to the public by milk sellers which is entirely 
fair and impartial. There can be no objection to publicity under 
such circumstances. It is an advantage to the seller of high-grade 
milk. It is an advantage to the consumer who desires to select a 
high-grade milk. It has much educational value both to producer 
and consumer. Therefore the commission recommends ''that the 
reports of laboratory analyses of milk made by departments of 
health be regularly published." 

Medical Inspection. 

It is the sense of the commission that the medical inspection 
of dairy employees should be emphasized in all ways possible. 

Milk Dealer's License. 

The commission resolved that a dealer shall be required to 
have a permit or license to sell any grade or class of milk and to 
use a label for such class or grade. Such permit or license shall 
be revoked and the use of the label forbidden when the local health 
authorities shall determine that the milk is not in the class or 
grade designated. 

Designation of Grade. 

The commission resolved that the grade of milk shall be desig- 
nated by letter. It is the sense of the commission that the essential 
part is the lettering and that all other words on the label are 
explanatory. 

In addition to the letters of the alphabet, used on caps or 
labels, the use of other terms may be permitted so long as such 
terms are not the cause of deception. 

Caps and labels shall state whether milk is raw or pasteurized. 
The letter designating the grade to which milk belongs shall be 
conspicuously displayed on the caps of bottles or the labels on cans. 

Classification of Milk. 

It was resolved that the classification of milk contained in 
the first report of the commission be amended as follows : 

Milk shall be divided into three grades, which shall be the 

16 



242 Principles of Legislative Milk Control. 

same for both large and small cities and towns, and wliicli shall 
be designated by the lirst three letters of the alphabet. The re- 
quirements shall be as follows : 

Grade A. 

Haw mill. — Milk of this class shall come from cows free from disease as determineil 
by tuberculin tests and physical examinations by a qualified veterinarian, and shall be 
produced and handled by employees free from disease as determined by medical inspection 
of a qualified physician, under sanitary conditions such that the bacteria count shall not 
exceed 100,000 per cul>ic centimeter at the time of delivery to the consumer. It is 
recommended that dairies from which this supply is obtained shall score at least 80 on 
the United States Bureau of Animal Industry score card. 

Pa.'^tciiriccd milt. — Milk of this plass shall come from cows free from disease as 
determined by physical examinations by a qualified veterinarian and shall be proiluced 
and handled under sanitary comlitions such that the bacteria count at no time exceeds 
200,000 per eu])ie centimeter. All milk of this class shall be pasteurized under official 
supervision, and the bacteria count shall not exceed 10,000 ])ev cubic centimeter at the 
time of delivery to the consumer. It is recommended that dairies from which this supjily 
is obtained should score 65 on the United States Bureau of Animal Industry score card. 

The above represents only the minimum standards under 
which milk may be classified in grade A. The commission recog- 
nizes, however, that there are grades of milk which are produced 
under unusually good conditions, in especially sanitary dairies, 
many of which are operated under the supervision of medical 
associations. Such milks clearly stand at the head of this grade. 

Grade B. 

]\Iilk of this class shall come from cows free from disease as determined by physical 
examinations, of which one each year shall be by a qualified veterinarian, and shall be 
produced and handled under sanitary conditions such that the bacteria count at no time 
exceeds 1,000,000 per cubic centimeter. All milk of this class shall be pasteurized under 
official supervision, and the bacteria count shall not exceed 50,000 per cubic centimeter 
when delivered to the consumer. 

It is recommended that dairies producing grade B milk should be scored and that 
the health departments or the controlling departments, whatever they may be, strive to 
bring these scores up as rapidly as possible. 

Grade C. 

Milk of this class shall come from cows free from disease as determined by physical 
examinations and shall include all milk that is produced under conditions such that the 
bacteria count is in excess of 1,000,000 per cubic centimeter. 

All milk of this class shall be pasteurized, or heated to a higher temperature, and 
shall contain less than 50,000 bacteria per cubic centimeter when delivered to the 
customer. It is recommended that this milk be used for cooking or manufacturing 
purposes only. 

Whenever any large city or community finds it necessary, on account of the length 
of haul or other peculiar conditions, to allow the sale of grade CI milk, its sale shall 
be surrounded by safeguards such as to insure the restriction of its use to cooking 
and manufacturing purposes. 

Classification of Cream. 

Cream should be classified in the same grades as milk, in 
accordance with the requirements for the grades of milk, excepting 
the bacterial standards which in 20 per cent cream shall not exceed 
five times the bacterial standard allowed in the grade of milk. 



Chemical Standards for Milk Products. 243 

Cream containing other percentages of fat shall be allowed 
a modification of this required bacterial standard in proportion 
to the change in fat. 

Chemical Standards. 

Cow's milk. — Standard milk should contain not less than 8.5 
per cent of milk solids not fat and not less than 3.25 per cent of 
milk fat. 

Shim milk. — Standard skim milk should contain not less than 
8.75 per cent of milk solids. 

Cream. — Standard cream contains not less than 18 per cent of 
milk fat and is free from all constituents foreign to normal milk. 
The percentage of milk fat in cream over or under that standard 
should be stated on the label. 

Buttermilk. — Buttermilk is the product that remains when fat 
is removed from milk or cream, sweet or sour, in the process of 
churning. Standard buttermilk contains not less than 8.5 per cent 
of milk solids. When milk is skimmed, soured, or treated so as 
to resemble buttermilk, it should be known by some distinctive 
name. 

Homogenized Milk or Cream. 

The commission is of the opinion that in the compounding of 
milk no fats other than milk fats from the milk in process should 
be used and that no substance foreign to milk should be added to it. 
The commission is opposed to the use of condensed milk or other 
materials for the thickening of cream unless the facts are clearly 
set forth on the label of the retail package. Regarding the process 
of homogenizing, the commission resolved as follows : 

That homoffenized milk or cream should be so marked, stating the percentage of 
fat that it contains. 

Adjusted Milks. 

On the question of milks and creams in which the ratio of the 
fats to the solids not fat has been changed by the addition to or 
subtractionof cream or milk fat the commission has hesitated to 
take a position. On the one hand they are in favor of every 
procedure which will increase the market for good milk and make 
the most profitable use of every portion of it. On the other, they 
recognize the sensitiveness of milk, the ease with which it is con- 
taminated, and the difficulty of controlling, standardizing, skim- 
ming, homogenizing, souring, etc., so that contaminations do not 
occur and inferior materials are not used. On this subject the 
commission passed a resolution presented by a special committee 
as follows : 

Milk in which the ratio of the fats to the solids not fat has been changed by the 
addition to or subtraction of cream should be labeled "adjusted milk"; the "label 
should show the minimum guaranteed percentage of fat and should comply with the 
same sanitary or chemical requirements as for milk not so standardised or modified. 



244 Princii)les of Lesiislativc ]\Iilk Coiilrol. 

Regulation of Market Milk on Basis of Guaranteed Percentage 

Composition. 

1. Sellers of milk should be permitted clioice of one of two 
systems in handling' market milk. Milk can be sold, first, under 
the regular standard, or, second, under a guaranteed statement of 
composition. 

2. Any normal milk may be sold if its per cent of fat is 
stated. In case the per cent of fat is not stated, the sale will be 
regarded as a violation unless the milk contains at least 3.25 per 
cent of milk fat. 

3. As a further protection to consumers, it is desirable that 
when the guaranty system is used there be also a minimum 
guaranty of milk solids not fat of not less than 8.5 per cent. 

4. Dealers electing to sell milk under the guaranty system 
should be required to state conspicuously the guaranty on all con- 
tainers in which such milk is handled by the dealer or delivered 
to the consumer. 

5. The sale of milk on a guaranty system should be by special 
permission obtained from some proper local authority. 

Penalty. 
Every milk ordinance should contain a penalty clause. 

Extension Work. 

The commission indorsed the efforts of the New York Milk 
Committee to obtain funds for the formation of a bureau of exten- 
sion work, such bureau to act as a collecting station for informa- 
tion regarding standards and regulations as to milk adopted by 
cities and towns in the United States. The Inireau should also 
furnish information to such cities and towns as appeal for aid 
in the adoption of milk standards and should conduct a construct- 
ive program by placing in the field a man who would visit com- 
munities interested in establishing milk standards; and it may 
use the members of the commission on milk standards for carrying 
on the work of the bureau so far as possible in their own localities. 

The commission has confined its report rather closely to the 
standard requirements for milk. These requirements can not he 
met unless proper measures are taken. For instance : The milk 
must be produced from healthy cows in clean surroundings, and 
must then be promptly chilled and kept cool thereafter. The hand- 
ling at all points must be done by healthy employees — employees 
w^ho are not carriers of contagion. 

The reports of the subcommittees on the methods of produc- 
tion, handling, and distribution, while not properly a part of the 
report itself, are set forth in the following pages. 



Licenses and Permits for Dealers. 245 



STANDARD RULES FOR THE PRODUCTION, HAN- 
DLING, AND DISTRIBUTION OF MILK. 

As a basis for the promulgation of rules and recommendations 
governing the production, handling, and distribution of milk, it is 
recognized that we have to deal with two kinds of milk, raw and 
pasteurized, although there may be several grades of each of these 
two kinds. In order for any grade to be safe, it is recommended 
that the regulations herein set forth under the heading "Ke- 
quirements'' should be enforced. The regulations herein set forth 
under the heading "Eecommendations" should be adopted wher- 
ever practicable as a means of improving the milk supply above 
the actual point of safety. (The term ''milk" shall be construed 
to include the fluid derivatives of milk wherever such construction 
of the term is applicable.) 

LICENSES. 

Requirements. 

No person shall engage in the sale, handling, or distribution 

of milk in until he has obtained a license therefor from the 

health authorities. This license shall be renewed on or before the 

1st day of of each year and may be suspended or revoked at 

any time for cause. 

Recommendations. 

The application for the license shall include the following statements: 

(1) Kind of milk to be handled or sold. 

(2) Names of producers with their addresses and permit numbers. 

(3) Names of middlemen with their addresses. 

(4) Names and addresses of all stores, hotels, factories, and restaurants at which 
milk is delivered. 

(5) A statement of the approximate number of quarts of milk, cream, buttermilk, 
and skim milk sold per day. 

(6) Source of water supply at farms and bottling plants. 

(7) Permission to inspect all local and out-of-town premises on which milk is 
produced and handled. 

(8) Agreement to abide by all the provisions of State and local regulations. 

PERMITS. 

Requirements. 

No person shall engage in the production of milk for sale in 
-, nor shall any person engage in the handling of milk for 



shipment into -' until he has obtained a permit therefor from 

the health authorities. This permit shall be renewed on or before 
the 1st day of of each year and may be suspended or re- 
voked at any time for cause. 



246 riiiK'i])k's of Legislative ^Milk ContiKl. 

PRODUCTION OF RAW MILK. 

Cow Stables. 

Requirements. 

1. They shall be used for no other purpose than for the keep- 
ing' of cows, and shall be light, well ventihited, and clean. 

2. They shall l)e ceih'd overhead if there is a loft above. 

3. The Hoors shall be tight and sound. 

4. The Slitters shall be water-tight. 



& 



Recommendations. 

1. The window area shall be at least 2 square feet per 500 cubic feet of air space 
and shall be nnifornily distributed, if possible. If uniform distribution is impossible, 
suflicient additional window area must be provided so that all portions of the barn shall 
be adequately lig^hted. 

2. The amount of air space shall be at least 500 cubic feet per cow, and adequate 
ventilation besides windows shall be provided. 

3. The walls and ceilings shall be whitewashed at least once every six months, 
unless the construction renders it unnecessary, and shall be kept free from cobwebs and 
dirt. 

4. All manure shall be removed at least twice daily, and disposed of so as not to be 
a source of danger to the milk either as furnishing a breeding place for flies or otherwise. 

5. Horse manure shall not be used in the cow stable for any purpose. 

Milk Room. 

Requirements. 

Every milk farm shall be provided with a milk room that is 
clean, light, and well screened. It shall be nsed for no other pur- 
pose than for the cooling, bottling, and storage of milk and the 
operations incident thereto. 

Recommendations. 

1. It shall have no direct connection with any stable or dwelling. 

2. The floors shall be of cement or other impervious material, properly graded and 
drained. 

3. It shall be provided with a sterilizer unless the milk is sent to a bottling plant, 
in which case the cans shall be sterilised at the plant. 

4. Cooling and storage tanks shall be drained and cleaned at least twice each week. 

5. All drains shall discharge at least 100 feet from any milk house or cow stalde. 

Cows. 

Requirements. 

1. A physical examination of all cows shall be made at least 
once every six months by a veterinarian approved by the health 
authorities. 

2. Every diseased cow shall be removed from the herd at 
once and no milk from such cows shall be offered for sale. 

3. The tuberculin test shall be applied at least once a year by 
a veterinarian approved by the health authorities. 



standards for Raw Milk. 247 

4. All cows wliicli react shall be removed from the herd at 
once, and no milk from such cows shall be sold as raw milk. 

5. No new cows shall be added to a herd until they have 
passed a physical examination and the tuberculin test. 

6. Cows, especially the udders, shall be clean at the time of 
milking. 

7. No milk that is obtained from a cow within 15 days before 
or 5 days after parturition, nor any milk that has an unnatural 
odor or appearance, shall be sold. 

8. No unwholesome food shall be used. 

Recommendations. 

1. Every producer shall allow a veterinarian employed by the health authorities 
to examine his herd at any time under the penalty of having his supply excluded. 

2. Certifieates showing the results of all examinations shall be filed with the health 
authorities within 10 days of such examinations. 

3. The tuberculin tests shall be applied at least once every six months by a veteri- 
narian approved by the health authorities, unless on the last previous test no tubercu- 
losis was present in the herd or in the herds from which new cows were obtained, in which 
event the test may be postponed an additional six months. 

4. Charts showing the results of all tuberculin tests shall be filed with the health 
authorities within 10 days of the date of such test. 

5. The udders shall be washed and wiped before milking. 

Employees. 

Requirements. 

1. All employees connected in any way with the production 
and handling of milk shall be personally clean and shall wear 
clean outer garments. 

2. The health authorities shall be notified at once of any 
communicable disease in any person that is in any way connected 
with the production or handling of milk, or of the exposure of 
such person to any communicable disease. 

3. Milking shall be done only with dry hands. 

Recommendations. 

1. Clean suits shall be put on immediately before milking. 

2. The hands shall be washed immediately before milking each cow, in order to 
avoid conveyance of infection to the milk. 

Utensils. 

Requirements. 

1. All utensils and apparatus with which milk comes in con- 
tact shall be thoroughly washed and sterilized, and no milk utensils 
or apparatus shall be used for any other purpose than that for 
which it was designed. 

2. The owner's name, license number, or other identification 
mark, the nature of which shall be made known to the health 



248 Principles of Legislative ^lilk Ctnitrol. 

aiitiiorities, shall appear in a conspicuous place on every milk 
container, 

3. No l)ottle or can shall he removed from a house in which 
there is, or in which there has recently been, a case of communi- 
cahle disease until permission in writing has been granted by the 
health authorities. 

4. All metal containers and piping shall be in good condi- 
tion at all times. All piping shall be sanitary milk piping, in 
couples short enough to be taken apart and cleaned with a brush. 

5. Small-top milking pails shall be used. 

Becom mend at ions. 

1. All cans and bottles shall be cleaned as soon as jiossildc after being emptied. 

2. Every convoyaiice used for transportation or delivery of milk, public carriers 
excepted, shall bear the owner's name, milk-license number, and business address in im- 
condensed gothic characters at least 2 inches in height. 

Handling of Milk. 
Requirements. 

1. It shall not be strained in the cow stable, but shall be 
removed to the milk room as soon as it is drawn from the cow. 

2. It shall be cooled to 50° F. or below within two hours 
after it is drawn from the cow and it shall be kept cold until it is 
delivered to the consumer. 

3. It shall not be adulterated by the addition to or the sub- 
traction of any substance or compound, except for the production 
of the fluid derivatives allowed by law. 

4. It shall not be tested by taste at any bottling plant, milk 
house, or other place in any way that may render it liable to 
contamination. 

5. It shall be bottled only in a milk room or bottling plant for 
which a license or permit has been issued. 

6. It shall be delivered in bottles, or single service containers, 
with the exception that 20 quarts or more may be delivered in bulk 
in the following cases : 

{a) To establishments in which milk is to be consumed or 
used on the premises. 

(b) To infant-feeding stations that are under competent 
medical supervision. 

7. It shall not be stored in or sold from a living room or from 
any other place which might render it liable to contamination. 

Recommendations. 

1. It shall be cooled to 50° F. or below immediately after milking and shall be 
kept at or below that temperature until it is delivered to the consumer. 

2. It shall contain no visible foreign material. 

3. It shall be labeled with the date of production. 



Standards for Raw Milk. 249 



Receiving Stations and Bottling Plants. 

Requirements, 

1. They shall be clean, well screened, and lighted, and shall 
be used for no other purpose than the proper handling of milk 
and the operations incident thereto, and shall be open to inspec- 
tion by the health authorities at any time. 

2. They shall have smooth, impervious floors, properly 
graded and drained. 

3. They shall be equipped with hot and cold water and steam. 

4. Ample provision shall be made for steam sterilization of 
all utensils, and no empty milk containers shall be sent out until 
after such sterilization. 

5. All utensils, piping, and tanks shall be kept clean and 
shall be sterilized daily. 

Recommendations. 

1. Containers and utensils shall not be washed in the same room in which milk is 
handled. 

Stores. 

Requirements. 

1. All stores in which milk is handled shall be provided with 
a suitable room or compartment in which the milk shall be kept. 
Said compartment shall be clean and shall be so arranged that the 
milk will not be liable to contamination of any kind. 

2. Milk shall be kept at a temperature not exceeding 50° F. 

Recommendations. 

_ 1. Milk to be consumed off the premises may be sold from stores only in the 
original unopened package. 

General Regulations. 

Requirements. 

1. The United States Bureau of Animal Industry score card 
shall be used, and it is recommended that dairies from which milk 
is to be sold in a raw state shall score at least 80 points. 

2. Every place where milk is produced or handled and every 
conveyance used for the transportation of milk shall be clean. 

3. All water supplies shall be from uncontaminated sources 
and from sources not liable to become contaminated. 

4. ^ The license or permit shall be kept posted in a conspicuous 
place m every establishment for the operation of which a milk 
license or permit is required. 

5. No milk license or permit shall at any time be used by anv 
person other than the one to whom it was granted. 



250 Principles of Legislative ^Nlilk Control. 

6. No ploco for tlio oporatioii of which a license or permit is 
granted shall be located within 100 feet of a privy or other possible 
source of contamination, nor shall it contain or open into a room 
which contains a water-closet. 

7. No skim milk or buttermilk shall be stored in or sold from 
cans or other containers unless such containers are of a distinctive 
color and permanently and conspicuously labeled ''skim milk" or 
''buttermilk," as the case may be. 

8. No container shall be used for any other purpose than 
that for which it is labeled. 

Recommendations. 

1. Tee useil for eoolins: purposes shall be clean and nncontaminated. 

2. No person whose presence is not required shall be permitted to remain in any 
cow stable, milk house, or bottling- room. 

SUBNORMAL MILK. 

Requirements. 
1. Natural milk that contains less than 3.25 per cent, but 
more than 2,5 per cent milk fat, and that complies in all other 
respects w^itli the requirements above set forth, may be sold, pro- 
vided the percentage of fat does not fall l^elow a definite percent- 
age that is stated in a conspicuous manner on the container; and 
further provided that such container is conspicuously marked 
"substandard milk." 

PRODUCTION OF CREAM. 

Requirements and Recommendations. 

1. It shall be obtained from milk that is produced and 
handled in accordance with the provisions hereinbefore set forth 
for the production and handling of milk. 

LABORATORY STANDARDS FOR MILK. 

Requirements. 

1. It shall not contain more than 100,000 bacteria per cubic 
centimeter. 

2. It shall contain not less than 3.25 per cent milk fat. 

3. It shall contain not less than 8.5 per cent solids not fat. 

Recommendations. 

1. The bacterial limit shall be lowered if possible. 

LABORATORY STANDARDS FOR CREAM. 

Requirements. 

1. There shall be a bacterial standard for cream correspond- 
ing to the grade of milk from which it is made and to its butter-fat 
content. 

2. It shall contain not less than 18 per cent, milk fat. 

Recommendations. 

Same as above for milk. 



Principles of Legislative Milk Control. 



251 



SANITARY INSPECTION OF CITY MILK PLANTS 



Owner or manager: 

Trade name: . Number 

Cream: . Permit or License No. 

Remarks: . 



SCOKE CARD. 

Street and No. :- 
of wagons: 



City; 



Gallons sold daily- 



Date of Inspection : 



State ; 
-Milk : 



191. 



Equipment. 


Score. 


Methods. 


Score. 


Perfect 


Alio wee 


Perfect Allowed 

- 1 


Build in?: 


li- 


2 
7 

12 
15 

2 

2 


1 


Building 


14 

7 

7 
22 

6 

4 




Location: Free from contan 
nating surroundings 


Cleanliness: 
Floors 3 




Arrangement 


Walls 2 




Separate receiving room. . . 


1 

2 

1 
1 

1 
1 


Ceilings 2 




Separate handling room. . . 

Separate wash room 

Separate salesroom 

Separate boiler room 

Separate refrigerator room. 


Doors and windows 1 

Shafting, pulleys, pipes, etc. 1 

Freedom from odors 2 

Freedom from flies 3 






Cleanliness: 
Thoroughly washed and 

rinsed 3 

Milk-handling machin- 




Floors tight, sound, cleanable 
Walls tight, smooth, clean'ble 
Ceiling smooth, tight, clean- 
able 


2 

1 

1 
2 

2 

2 
1 

1 

2 

2 
2 

1 
1 

1 
6 

1 

1 




Drainage 

Floors 1 

Sewer or septic tank... 1 

Provision for light 

(10 per cent of floor space. 

Provision for pure air 

Screens 


Pipes, cans, etc 1 

Sterilized with live steam. . 3 

Milk-handling machin- 
ery 2 

Pipes, cans, etc 1 

Protected from contamina- 




Minimum of shafting, pul- 


Bottles 




leys, hangers, exposed 

pipes, etc 

Apparatus 

Boiler 


Thoroughly washed and 
rinsed 3 

Sterilized with steam 15 min- 
utes 3 

Inverted in clean place 1 

Handling milk 

Received below 50° F 3 

(50° to 55°, 2) ; (55° to 600,1.) 

Rapidity of handling 2 

Freedom from undue expos- 
ure to air 2 


! 


(Water heater, 1.) 
Appliances for cleansing 

utensils and bottles 

Sterilizers for bottles, etc . . . 

Bottling machine 

Capping machine 

Wash bowl, soap, and towel 





in handling room 






Condition 

Milk-handling machinery 3 
Pipes, couplings, and 


Promptness 2 

Below 45° F 3 

(45° to 50°, 1.) 
Capping bottles by machine. 2 
Bottle top protected by cover 1 

Storage; below 45°F 4 

(45° to 50°, 3; 50° to 55°, 1.) 
Protection during delivery. . 2 
(Iced in summer.) 

Bottle caps sterilized 1 

Inspection 


1 


Cans 1 

Laboratory and equipment. . . 
Water supply 

Clean and fresh 

Convenient and abundant . . . 


1 




Bacteriological work 3 

Inspection of dairies supply- 
ing milk 3 






(2 times a year, 2; once a 
year, 1.) 
Miscellaneous 






Cleanliness of attendants... 2 

Personal cleanliness 1 

Clean, washable clothing. . . 1 

Cleanliness of delivery outfit 2 

Total 






40 


1 




Total 


60 





Score of equipment + Score for Methods = Total Score. 

NOTE — If the conditions in any particular are so exceptionally bad as to be inadequately ex- 
pressed by a score of "0" the inspector can make a deduction from the total score. 



[C'ir. 199] 



Inspector. 



252 



Score Card i'nv Dnirv Farms. 



SANITARY INSPECTION OF DAIRY FARMS 

SC'OKE CAIU). 

Iiulorsed bj' the Ollioial Dairy lustructoi'.s Association. 

Owner or lessee of farm: . P. O. address: . State: 

Total number of c-ows: . Nmnber nulkinj;: . Gallons of nnlk produced 

daily: . Product is sold by prochicer in fanulies,- hotels, restaurants, stores, to 



-dealer. For milk supply of 
-. Eemarks : 



Pernut No. 



(Signed) 



Date of inspection. 
Inspector. 



Equipment 


Score. 1 


Methods. 


Score. 


Perfect .Vllowed 


PerfectlAUowed 


Cows. 
Health 


6 

1 
1 

2 

4 

4 

1 

7 

1 
1 

5 
1 

1 

1 

2 

1 

1 

40 




Cows. 


8 
6 

5 

1 
2 

2 
3 
8 

9 

2 

2 

5 

3 

tjo 




Apparently in good health.. 1 
If tested with tuberculin 
within a year and no tuber- 
culosis is found, or if tested 
within six months and all 


(Free from visible dirt, 6.) 
Stables. 




reacting animals removed. 5 

(If tested within a year and 

reacting animals are found 

and removed, 3.) 

Food (clean and wholesome).. . 

Water (clean and fresh) 

Stables. 


Floor 2 

Walls 1 

Ceiling and ledges 1 

Mangers and partitions. ... 1 
Windows 1 

Stable air at milking time 

Freedom from dust 3 

Freedom from odors 2 

Cleanliness of bedding 


1 


Well drained 1 

Free from contaminating sur- 
roundings 1 

Construction of stable 

Tight, sound floor and proper 
gutter 2 

Smooth, tight walls and ceil- 




Clean 1 








Removal of manure daily to 50 
feet from stable 

Milk Room or Milk House. 
Cleanliness of milk room 

Utensils and Milking. 
Care and cleanliness of utensils 

Thoroughly wasned 2 

Sterlized in steam for 15 

minutes 3 

(Places over steam jet, or 
scalded with boiling 
water, 2.) 
Protected from contamina- 
tion 3 

Cleanliness of milking 

Clean, dry hands 3 

Udders waslied and wiped. . 6 

(Udders cleaned with moist 

cloth, 4; cleaned with dry 

cloth or brush at least 15 

minutes before milking, 1.) 

Handling the Milk. 
Cleanliness of attendants in 




Proper stall, tie, and manger 1 
Provision for light: Four sq. ft., 




(Three sq. ft., 3: 2 sq. ft., 2; 
1 sq. ft., 1. Deduct for un- 
even distribution.) 
Bedding 








Provision for fresh air, con- 
trollable flue system 3 

(Windows hinged at bot- 
tom, 1.5; sliding win- 
dows, 1; other openings, 
0.5.) 
Cubic feet of space per cow 
500 ft 




(Less than 500 ft., 2; less 
than 400 ft., 1; less than 
300 ft., 0.) 
Provision for controlling 
temperature 1 

Utensils. 




Construction and condition of 


Milk removed immediately from 
stable without pouring from 




Water for cleaning 




(Clean, convenient, and abun- 
dant.) 


Cooled immediately after milk- 




Small-top milking pail 


Cooled below 50° F 

(51° to 55°, 4: 56° to 60°, 2.) 




Clean milking suits 




Jlilk Room or Jrilk House. 
Location: Free from contaminat- 


(51° to 55°. 2: 56° to 60°, 1.) 
Transportation below 50° F. . . 
(51° to 55°, 1.5;56° to 60°, 1.) 
(If delivered twice a day, al- 
low perfect score for storage 
and transportation.) 

Total 




Construction of milk room 

Floor, walls, and ceiling. ... 1 
Ligl.t, ventilation, screens, . . 1 

Separate rooms for washing 
utensils and handling milk . . . 




(Hot water, 0.5.) 




Total 








Equipment + :\fetho(1s = Final Score. 

NOTE 1. — If any excentionally filthy condition is found, particularly dirty utensils, the total 
score may be further limited. . . 

NOTE 2. — If the water is exposed to dangerous contamination, or there is evidence of the pres- 
ence of a dangerous disease in animals or attendants, the score shall be 0. 
ICir, 199J 



Standards for Pasteui'ized Milk. 253 



STANDARDS FOR SKIM MILK. 

Requirements. 

1. It shall contain not less than 8.75 per cent milk solids. 

2. Control of sale of skim milk: Whether skim milk is sold 
in wagons or in stores all containers holding skim milk should be 
painted some bright, distinctive color and prominently and legibly 
marked ''skim milk." When skim milk is placed in the buyer's 
container, a label or tag bearing the words "skim milk" should 
be attached. 

PRODUCTION OF PASTEURIZED MILK 

Pasteurized milk is milk that is heated to a temperature of 
not less than 140° F. for not less than 20 minutes, or not over 
155° F. for not less than 5 minutes, and for each degree of tem- 
perature over 140° F. the length of time may be 1 minute less 
than 20. Said milk shall be cooled immediately to 50° F. or below 
and kept at or below that temperature. 

Cow Stables. 

Requirements. 
The same as for the production of raw milk. 

Recommendations. 

The same as for the production of raw milk. 

Milk Room. 

Requirements. 
The same as for the production of raw milk. 

Recommendations. 

The same as for the production of raw milk. 

Cows. 

Requirements. 

The same as for the production of raw milk, with the excep- 
tion of the sections relating to the tuberculin test. 

Recommiendations. 

That no cows be added to a herd excepting those found to be free from tuberculosis 
by the tuberculin test. 

Employees. 

Requirements. 
The same as for the production of raw milk. 



254 Principles of Legislative Milk Control. 

Rpco)iu)i(')i(l(ifio)is. 

The same as for the piodiu'tion of raw milk. 

Utensils. 

Rcquironcnfs. 
The same as for the production of raw milk. 

Recommend ai ions. 

The same as for tlic production of raw milk. 

Milk for Pasteurization. 

Requirements. 

1. The same as for the production of raw milk, witli the ex- 
ception of sections 1, 2, and Qh. 

2. It sliall ])e cooled to 60° F. or below within two liours 
after it is drawn from the cow, and it shall be held at or below 
tliat temperature until it is pasteurized. After pasteurization, it 
shall be held at a temperature not exceeding 50° F. until delivered 
to the consumer. 

3. Pasteurized milk shall be distinctly labeled as such, to- 
gether with the temperature at which it is pasteurized and the 
shortest length of exposure to that temperature and the date of 
pasteurization. 

Recom m endations. 

1. Xo milk shall be repastenrized. 

2. The requirements governing the production and handling of milk for pas- 
teurization should be raised wherever practicable. 

Pasteurizing Plants. 

Requirements. 

The same as under "Receiving stations and bottling plants" 
for raw milk. 

Recommendations. 

The same as under "Eeceiving stations and bottling plants" for raw milk. 

Stores. 

Requirements. 
The same as for raw milk. 

Recommendations. 

The same as for raw milk. 



Standards for Pasteurized Milk. 255 



General Regulations. 

Requirements. 

1. It is recommended that dairies producing milk wliich is 
to be pasteurized shall be scored on the United States Bureau of 
Animal Industry score card, and that health departments, or the 
controlling departments whatever they may be, strive to bring 
these scores up as rapidly as possible. 

2. Milk from cows that have been rejected by the tuberculin 
test, but which show no physical signs of tuberculosis, as well as 
those which have not been tested, may be sold provided that it is 
produced and handled in accordance with all the other require- 
ments herein set forth for pasteurized milk. 

3. Ice used for cooling purposes shall be clean. 

Recommendations. 

The same as for raw milk. 

PRODUCTION OF PASTEURIZED CREAM. 

Requirements. 

1. It shall be obtained only from milk that could legally be 
sold as milk under the requirements hereinbefore set forth. 

2. Pasteurized cream, or cream separated from pasteurized 
milk, shall be labeled in the manner herein provided for the label- 
ing of pasteurized milk. 

STANDARDS FOR PASTEURIZED MILK. 

Requirements. 

1. It shall not contain more than 1,000,000 bacteria per cubic 
centimeter before pasteurization, nor over 50,000 when delivered 
to the consumer. 

2. The standards for the percentage of milk fat and of total 
solids shall be the same as for raw milk. 

Recommendations. 

1. The limits for the bacterial connt before pasteurization and after pasteurization 
should both be lowered if possible. 

STANDARDS FOR PASTEURIZED CREAM. 

Requirements. 

1. No cream shall be sold that is obtained from pasteurized 
milk that could not be legally sold under the provisions herein set 
forth, nor shall any cream that is pasteurized after separation 
contain an excessive number of bacteria. 



256 Principles of Legislative IMilk Control. ^ 

2. There shall be a bacterial standard for pasteurized cream 
coi'respoiidiiig to the grade of milk from which it is made and to 
its biitterfat content. 

;j. The percentage of milk fat shall be the same as for raw 
cream. 

SANITARY INSPECTION OF MILK PLANTS AND DAIRY FARMS. 

Bh^nk forms of the latest United States Bureau of Animal 
Industry score cards wliicli have been ])reviously referred to, are 
shown on pages 251-252. Experience has shown that there is no 
system of sanitary inspection so efficient as that obtained b}^ the use 
of these cards. Every condition pertaining to the milk is considered 
and rated mathematically according to its importance. The com- 
pleted score gives an accurate survey of the facts in a comparative 
manner which may serve as a permanent record, far more reliable 
in character than is a mere inspection unaided by the score card. 
This system not only provides a uniform and systematic summary, 
but it also has a tendency to stimulate the producer to increased 
eH'orts in overcoming the defects which reduce his total score. 

PRODUCTION OF AND STANDARDS FOR CERTIFIED MILK. 

The methods and standards for the production and distribu- 
tion of certified milk, adopted by the American Association of 
Medical Milk Commissions, May 1, 1912, contain all the necessary 
provisions for the preparation of this special milk which undoubt- 
edly leads all classes of milk as a food for infants. 

Hygiene of the Dairy. 

UNDER THE SUPERVISION" AND CONTROL OF THE VETERINARIAN. 

1. Pastures or paddochs. — Pastures or paddocks to which 
the cows have access shall l)e free from marshes or stagnant pools, 
crossed by no stream which might become dangerously contami- 
nated, at sufficient distances from offensive conditions to suffer 
no bad effects from them, and shall be free from plants which 
affect the milk deleteriously. 

2. Surround ill OS of hnildinqs. — The surroundings of all 
buildings shall be kept clean and free from accumulations of dirt, 
rubbish, decayed vegetable or animal matter or animal waste, and 
the stable yard shall be well drained. 

3. Lnrafion of huildinr/s. — Buildings in which certified milk 
is produced and handled shall be so located as to insure proper 
shelter and good drainage, and at sufficient distance from other 
buildings, dusty roads, cultivated and dusty fields, and all other 
possil)le sources of contamination ; provided, in the case of un- 
avoidable proximity to dusty roads or fields, the exposed side 
shall be screened with cheesecloth. 



Standards for Certified Milk. 257 



4. Construction of stables.— The stables shall be constructed 
so as to facilitate the prompt and easy removal of waste products. 
The floors and platforms shall be made of cement or other non- 
absorbent material and the gutters of cement only. The floors 
shall be properly graded and drained, and the manure gutters 
shall be from 6 to 8 inches deep and so placed in relation to the 
platform that all manure will drop into them. 

5. The inside surface of the walls and all interior construc- 
tion shall be smooth, with tight joints, and shall be capable of 
sheddmg water. The ceiling shall be of smooth material and dust 
tight. All horizontal and slanting surfaces which might harbor 
dust shall be avoided. 

6. Drinking and feed troughs. — Drinking troughs or basins 
shall be drained and cleaned each day, and feed troughs and mix- 
ing floors shall be kept in a clean and sanitary condition. 

^ 7. Stanchions.— ^ta-nchions, when used, shall be constructed 
of iron pipes or hardwood, and throat latches shall be provided 
to prevent the cows from lying down between the time of cleaning 
and the time of milking. 

8. Ventilation.— The cow stables shall be provided with ade- 
quate ventilation either by means of some approved artificial de- 
vice, or by the substitution of cheesecloth for glass in the windows, 
each cow to be provided with a minimum of 600 cubic feet of air 
space. 

9. Windows. — A sufficient number of windows shall be in- 
stalled and so distributed as to provide satisfactory light and a 
maximum of sunshine, 2 feet square of window area to" each 600 
cubic feet of air space to represent the minimum. The coverings 
of such windows shall be kept free from dust and dirt. 

10. Exclusion of flies, etc.—A\\ necessary measures should 
be taken to prevent the entrance of flies and other insects and 
rats and other vermin into all the buildings. 

11. Exclusion of animals from the herd. — No horses, hogs, 
dogs, or other animals or fowls shall be allowed to come in contact 
with the certified herd, either in the stables or elsewhere. 

12. Bedding.— ^0 dusty or moldy hay or straw, bedding from 
horse stalls, or other unclean materials shall be used for bedding 
the cows. Only bedding which is clean, dry, and absorbent may 
be used, preferably shavings or straw. 

13. Cleaning stable and disposal of manure. — Soiled bedding 
and manure shall be removed at least twice daily, and the floors 
shall be swept and kept free from refuse. Such cleaning shall be 
done at least one hour before the milking time. Manure, when 
removed, shall be drawn to the field or temporarilv stored in con- 
tainers so screened as to exclude flies. Manure shall not be even 
temporarily stored within 300 feet of the barn or dairy building. 

14. Cleaning of cows.— Fiach cow in the herd shall be groomed 
daily, and no manure, mud, or filth shall be allowed to" remain 



258 Piiiiciplos of Loiiislative ]\Iilk Control. 

upon her during milking; for cleaning, a vacnnni apparatus is 
reconnnended. 

15. Clipping. — Long hairs shall be clipped from the udder 
and flanks of the cow and from the tail above the brush. The hair 
on the tail shall be cut so that the brush may be well above the 
ground. 

16. Cleaning of iidders. — The udders and teats of the cow 
shall be cleaned before milking; they shall be washed with a cloth 
and water, and dry wiped with another clean sterilized cloth — a 
separate cloth for drying each cow. 

17. Feeding. — All foodstuffs shall be kept in an apartment 
separate from and not directl}^ communicating with the cow barn. 
They shall be brought into the barn only immediately before the 
feeding hour, which shall follow the milking. 

18. Only those foods shall be used which consist of fresh, 
palatable, or nutritious materials, such as will not injure the 
health of the cows or unfavorably affect the taste or character 
of the milk. Any dirty or moldy food or food in a state of de- 
composition or putrefaction shall not be given. 

19. A well-balanced ration shall be used, and all changes of 
food shall be made slowly. The first few feedings of grass, alfalfa, 
ensilage, green corn, or other green feeds shall be given in small 
rations and increased gradually to full ration. 

20. Exercise. — All dairy cows shall be turned out for exer- 
cise at least 2 hours in each 24 in suitable weather. Exercise 
yards shall be kept free from manure and other filth. 

21. Washing of hands. — Conveniently located facilities shall 
be provided for the milkers to wash in before and during milking. 

22. The hands of the milkers shall be thoroughly washed 
with soap, water, and brush and carefully dried on a clean towel 
immediately before milking. The hands of the milkers shall be 
rinsed with clean water and carefully dried before milking each 
cow. The practice of moistening the hands with milk is forbidden. 

23. Milking clothes. — Clean overalls, jumper, and cap shall 
be worn during milking. They shall be washed or sterilized each 
day and used for no other purpose, and when not in use they 
shall be kept in a clean place, protected from dust and dirt. 

24. Things to he avoided, hy millxers. — While engaged about 
the dairy or in handling the milk employees shall not use tobacco 
nor intoxicating liquors. They shall keep their fingers away from 
their nose and mouth, and no milker shall permit his hands, 
fingers, lips, or tongue to come in contact with milk intended for 
sale. 

25. During milking the milkers shall be careful not to touch 
anything but the clean top of the milking stool, the milk pail, and 
the cow's teats. 

26. Milkers are forbidden to spit upon the walls or floors 



standards for Certified Milk. 259 

of stables, or upon the walls or floors of milk houses, or into the 
water used for cooling the milk or washing the utensils. 

27. Fore milk. — The first streams from each teat shall be 
rejected, as this fore milk contains large numbers of bacteria. 
Such milk shall be collected into a separate vessel and not milked 
onto the floors or into the gutters. The milking shall be done 
rapidly and quietly, and the cows shall be treated kindly. 

28. Milk and calving period. — Milk from all cows shall be ex- 
cluded for a period of 45 days before and 7 days after parturition. 

29. Bloody and stringy milk. — If milk from any cow is 
bloody and stringy or of unnatural appearance, the milk from 
that cow shall be rejected and the cow isolated from the herd 
until the cause of such abnormal appearance has been determined 
and removed, special attention being given in the meantime to 
the feeding or to possible injuries. If dirt gets into the pail, the 
milk shall be discarded and the pail washed before it is used. 

30. Make-up of herd. — No cows except those receiving the 
same supervision and care as the certified herd shall be kept in 
the same barn or brought in contact with them. 

31. Employees other than milkers. — The requirements for 
milkers, relative to garments and cleaning of hands, shall apply 
to all other persons handling the milk, and children unattended by 
adults shall not be allowed in the dairy nor in the stable during 
milking. 

32. Straining and strainers. — Promptly after the milk is 
drawn it shall be removed from the stable to a clean room and 
then emptied from the milk pail to the can, being strained through 
strainers made of a double layer of finely meshed cheesecloth or 
absorbent cotton thoroughly sterilized. Several strainers shall 
be provided for each milking in order that they may be frequently 
changed. 

33. Dairy building. — A dairy building shall be provided 
which shall be located at a distance from the stable and dwelling 
prescribed by the local commission, and there shall be no hogpen, 
privy, or manure pile at a higher level or within 300 feet of it. 

34. The dairy building shall be kept clean and shall not be 
used for the purposes other than the handling and storing of milk 
and milk utensils. It shall be provided with light and ventilation, 
and the floors shall be graded and water-tight. 

35. The dairy building shall be well lighted and screened 
and drained through well-trapped pipes. No animals shall be 
allowed therein. No part of the dairy building shall be used for 
dwelling or lodging purposes, and the bottling room shall be used 
for no other purpose than to provide a place for clean milk uten- 
sils and for handling the milk. During bottling this room shall be 
entered only by persons employed therein. The bottling room 
shall be kept scrupulously clean and free from odors. 

36. Tem^perature of milk. — Proper cooling to reduce the tem- 



260 Principles of Legislative Milk Control. 



pcratiire to 45'' F. sliall ]>e used, and aerators shall be so situated 
that they can be protected from flies, dust, and odors. The milk 
shall be cooled immediately after being milked, and maintained 
at a temperature between 35° and 45° F. until delivered to the 
consumer. 

37. Sealing of bottles. — Milk, after being- cooled and bottled, 
shall be immediately sealed in a manner satisfactory to the com- 
mission, but such seal shall include a sterile hood which com- 
pletely covers the lip of the bottle. 

38. Cleaning and sterilizing of bottles. — The dairy building 
sliall be jDrovidcd with approved apparatus for the cleansing and 
sterilizing of all bottles and utensils used in milk production. 
All bottles and utensils shall be thoroughly cleaned by hot water 
and sal soda, or equally pure agent, rinsed until the cleaning 
water is thoroughly removed, then exposed to live steam or boil- 
ing water at least 20 minutes, and then kept inverted until used, 
in a place free from dust and other contaminating materials. 

39. Utensils. — All utensils sliall be so constructed as to be 
easily cleaned. The milk pail should preferably have an elliptical 
opening 5 by 7 inches in diameter. The cover of this pail should 
be so convex as to make the entire interior of the pail visible and 
accessible for cleaning. The pail shall be made of heavy seamless 
tin, and with seams w^hich are flushed and made smooth by solder. 
Wooden pails, galvanized-iron pails, or pails made of rough, 
porous materials, are forbidden. All utensils used in milking 
shall be kept in good repair. 

40. Water supply. — The entire water supply shall be abso- 
lutely free from contamination, and shall be sufficient for all dairy 
purposes. It shall be protected against flood or surface drainage, 
and shall be conveniently situated in relation to the milk house. 

41. Privies, etc., in relation to ivater supply. — Privies, pig- 
pens, manure piles, and all other possible sources of contamina- 
tion shall be so situated on the farm as to render impossible the 
contamination of the water supply, and shall be so protected by 
use of screens and other measures as to prevent their becoming 
breeding grounds for flies. 

42. Toilet rooms. — Toilet facilities for the milkers shall be 
provided and located outside of the stable or milk house. These 
toilets shall be properly screened, shall be kept clean, and shall 
be accessible to wash basins, water, nail brush, soap and towels, 
and the milkers shall be required to wash and dry their hands 
immediately after leaving the toilet room. 

Transportation. 

43. In transit the milk packages shall be kept free from dust 
and dirt. The wagon, trays, and crates shall be kept scrupulously 
clean. No bottles shall be collected from houses in which com- 
municable diseases prevail, unless a separate wagon is used and 



standards for Certified Milk. 261 



under conditions prescribed by the department of health and the 
medical milk commission. 

44. All certified milk shall reach the consumer within 30 
hours after milking. 

Veterinary Supervision of the Herd. 

45. Tuberculin test. — The herd shall be free from tubercu- 
losis, as shown by the proper application of the tuberculin test. 
The test shall be applied in accordance with the rules and regula- 
tions of the United States Government, and all reactors shall be 
removed immediately from the farm. 

46. No new animals shall be admitted to the herd without 
first having passed a satisfactory tuberculin test, made in accord- 
ance with the rules and regulations mentioned; the tuberculin to 
be obtained and applied only by the official veterinarian of the 
commission, 

47. Immediately following the application of the tuberculin 
test to a herd for the purpose of eliminating tuberculous cattle, 
the cow stable and exercising yards shall be disinfected by the 
veterinary inspector in accordance with the rules and regulations 
of the United States Government. 

48. A second tuberculin test shall follow each primary test 
after an interval of six months, and shall be applied in accord- 
ance with the rules and regulations mentioned. Thereafter, tuber- 
culin tests shall be reapplied annually, but it is recommended 
that the retests be applied semi-annually. 

49. Identification of cows. — Each dairy cow in each of the 
certified herds shall be labeled or tagged with a number or mark 
which will permanently identify her. 

50. Herd-hook record.— E^ach cow in the herd shall be regis- 
tered in a herd book, which register shall be accurately kept so 
that her entrance and departure from the herd and her tuberculin 
testing can be identified. 

51. A copy of this herd-book record shall be kept in the 
hands of the veterinarian of the medical milk commission under 
which the dairy farm is operating, and the veterinarian shall be 
made responsible for the accuracy of this record. 

52. Dates of tubercidin tests.— Tlie dates of the annual tu- 
berculin tests shall be definitely arranged by the medical milk 
commission, and all of the results of such tests shall be recorded 
by the veterinarian and regularly reported to the secretary of 
fi^e medical milk commission issuing the certificate. 

53. The results of all tuberculin tests shall be kept on file 
by each medical milk commission, and a copy of all such tests 
shall be made available to the American Association of Medical 
Milk Commissions for statistical purposes. 

^ 54. The proper designated officers of the American Associa- 
tion of Medical Milk Commissions should receive copies of reports 



262 Principles of Legislative Milk Control. 



of all of tlio ainiiial, scmiaiuiual, aiul other official tuberculin tests 
which are made and keep copies of the same on file and compile 
them annually for the use of the association. 

55. Disposition of coivs sick ivith diseases other than tuber- 
culosis. — Cows having- rheumatism, leucorrhea, inflannnation of 
the uterus, severe diarrhea, or disease of the udder, or cows that 
from any other cause may be a menace to the herd shall be re- 
moved from the herd and placed in a building separate from that 
which nuiy be used for the isolation of cows with tuberculosis, 
unless such building has been properly disinfected since it was 
last used for this purpose. The milk from such cows shall not 
be used nor shall the cows be restored to the herd until permission 
has been given by the veterinary inspector after a careful physical 
examination. 

56. Nofificafioii of veterinary inspector. — In the event of 
the occurrence of any of the diseases just described between the 
visits of the veterinary inspector, or if at any time a number of 
cows become sick at one time in such a way as to suggest the 
out])reak of a contagious disease or poisoning, it shall be the duty 
of the dairyman to withdraw such sickened cattle from the herd, 
to destroy their milk, and to notify the veterinary inspector by 
telegraph or telephone immediately. 

57. Emaciated coivs. — Cows that are emaciated from chronic 
diseases or from any cause that in the opinion of the veterinary 
inspector may endanger the quality of the milk, shall be removed 
from the herd. 

Bacteriological Standards. 

58. Bacterial counts. — Certified milk shall contain less than 
10,000 bacteria per cubic centimeter when delivered. In case a 
count exceeding 10,000 bacteria per cubic centimeter is found, 
daily counts shall be made, and if normal counts are not restored 
within 10 days the certificate shall be suspended. 

59. Bacterial counts shall be made at least once a week. 

60. Collection, of samples. — The samples to be examined shall 
be obtained from milk as offered for sale and shall be taken by a 
representative of the milk commission. The samples shall be 
received in the original packages, in properly iced containers, and 
they shall be so kept until examined, so as to limit as far as 
possible changes in their bacterial content. 

61. For the purpose of ascertaining the temperature, a sep- 
arate original package shall be used, and the temperature taken 
at the time of collecting the sample, using for the purpose a 
standardized thermometer graduated in the centigrade scale. _ 

62. Interval hetiveen milhinr/ and platinr/. — The examinations 
shall be made as soon after collection of the samples as possible, 
and in no case shall tlie int(U'val between milking and plating the 
samples be longer than 40 hours. 



standards for Certified Milli. 263 

63. Plating. — The packages shall be opened with aseptic pre- 
cautions after the milk has been thoroughly mixed by vigorously 
reversing and shaking the container 25 times. 

64. Two plates at least shall be made for each sample of 
milk, and there shall also be made a control of each lot of medium 
and apparatus used at each testing. The plates shall be grown 
at 37° C. for 48 hours. 

65. In making the plates there shall be used agar-agar media 
containing 1.5 per cent agar and giving a reaction of 1.0 to phe- 
nolphthalein. 

The following is the method recommended by a committee 
of the American Public Health Association for the making of the 
media, modified, however, as to the agar content and reaction to 
conform to the requirements specified in section 65 : 

1. Boil 15 grams of thread agar in 500 e. e. of water for half an hour and make 
np weight to 500 grams or digest for 10 minutes in the autoclave at 110° C. Let this 
cool to about 60° C. 

2. Infuse 500 grams finely chopped lean beef for 24 hours with its own weight of 
distilled water in the refrigerator. 

3. Make up any loss by evaporation. 

4. Strain infusion through cotton flannel, using pressure. 

5. Weigh filtered infusion. 

6. Add Witte's peptone, 2 per cent. 

7. Warm on water bath, stirring until peptone is dissolved and not allowing 
temperature to rise above 60° C. 

8. To the 500 grams of meat infusion (with peptone) add 500 grams of the 2 per 
cent agar, keeping the temperature below 60° C. 

9. Heat over boiling water (or steam) bath 30 minutes. 

10. Restore weight lost by evaporation. 

11. Titrate after boiling one minute to expel carbonic acid. 

12. Adjust reaction to final point desired +1 by adding normal sodium hydrate. 

13. Boil two minutes over free flame, constantly stirring. 

14. Restore weight lost by evaporation. 

15. Filter through absorbent cotton or coarse filter paper, passing the filtrate 
through the filter repeatedly until clear. 

16. Titrate and record the final reaction. 

17. Tube (10 c. e. to a tube) and sterilize in autoclave one hour at 15 pounds 
pressure or in the streaming steam for 20 minutes on three successive days. 

QQ. Samples of milk for plating shall be diluted in the pro- 
portion of 1 part of milk to 99 parts of sterile water; shake 25 
times and plate 1 c. c. of the dilution. 

The committee on bacterial milk analyses of the American Public Healtli 
Association in Part IV of its report presented details with respect to plating apparatus 
and technique in part as follows : 

Plating apparatus. — For plating it is best to have a water bath in which to melt 
the media and a water-jacketed water bath for keeping it at the required temperature; 
a wire rack which should fit both the water baths for holding the media tubes; a ther- 
mometer for recording the temperature of the water in the water-jacketed bath, sterile 1 
c. c. pipettes, sterile Petri dishes, and sterile dilution water in measured quantities. 

Dilutions. — Ordinary potable water, sterilized, may be used for dilutions. Oc- 
casionally spore forms are found in such water which resist ordinary autoclave steriliza- 
tion ; in sucli cases distilled water may be used or the autoclave pressure increased. With 
dilution water in 8-ounce bottles calibrated for 99 cubic centimeters * * * all the 
necessary dilutions may be made. 

Short, wide-mouthed "blakes" or wide-mouthed French square bottles are more 
easily handled and more economical of space than other forms of bottles or flasks. 

Eight-ounce bottles are the best, as the required amount of dilution water only 
about half fills them, leaving room for shaking. Long-fiber nonabsorbent cotton should 



264 Principles of Legislative Milk Control. 

lie used for plugs. It is well to use care in selecting cotton for this purpose to avoid 
short-fiber or dusty cotton, which give a cloud of lint-like particles on shaking. Bottles 
* * * should be filled a little over the 99 e. c. * * * to allow for loss during 
sterilization. 

Pipettes. — Straight sides 1 c. c. pipettes are more easily handled than those with 
bulbs; they may be made from ordinary three-sixteenths inch glass tubing and should 
be about 10 inches in length. 

Plalin;/ /< c/; /(/(/(/ c. — The agar after melting should lo kept in the water-jacketed 
water bath between 40° C. and 45° C. for at least 15 minutes before using to make 
sure that the agar itself has reached tlie temperature of the surrounding water. If 
used too warm the heat may destroy some of the bacteria or retard their growth. 

Shake the milk sample 25 times, then with a sterile pipette transfer 1 c. c. to the 
first dilutior Abater and rinse the pipette by drawing dilution water to the mark and ex- 
pelling; this gives a dilution 1 to 100. 

* * * Then with a sterile pipette transfer 1 c. c. to the Petri dish, using care 
to raise the cover only as far as necessary to insert the end of the pipette. 

Take the tulie of agar from the water bath, wipe the water from outside the tube 
with a piece of cloth, remove the plug, pass the mouth of the tube through a flame, and 
pour the agar into the plate, using the same care as before to avoid exposure of the 
plate contents to the air. 

Carefully and thoroughly mix the agar and diluted milk in the Petri dish by a 
rotary motion, avoiding the formation of air bulibles or slopping the agar, and after 
allowing the agar to harden for at least 15 minutes at room temperature, place the dish 
bottom down in the incubator. 

Plating should always be done in a place free from dust or currents of air. 

In order that colonies may have sufficient food for proper development 10 c. e. of 
agar shall be used for each plate. 

67. Determination of taste and odor of milk. — After the 
plates have been prepared and placed in the incubator, the taste 
and odor of the milk shall be determined after warming the milk 
to 100° F. 

68. Counts. — The total number of colonies on each plate 
should be counted, and the results expressed in multiples of the 
dilution factor. Colonies too small to be seen with the naked eye 
or with slight magnification shall not be considered in the count. 

69. Records of hacteriologic tests. — The results of all bac- 
terial tests shall be kept on file by the secretary of each commis- 
sion, copies of which should be made available annually for the 
use of the American Association of Medical Milk Commissions. 

Chemical Standards and Methods. 

The methods that must be followed in carrying out the chemi- 
cal investigations essential to the protection of certified milk are 
so complicated that in order to keep the fees of the chemist at 
a reasonable figure, there must be eliminated from the examination 
those procedures which, whilst they might be helpful and interest- 
ing, are in no sense necessary. 

For this reason the determination of the water, the total 
solids and the milk sugar is not required as a part of the routine 
examination. 

70. The chemical analyses shall be made by a competent 
chemist designated by the medical milk commission. 

71. Method of ohtaininf) samples. — The samples to be exam- 
ined by the chemist shall have been examined previously by the 



standards for Certified Milk. 265 

bacteriologist designated by the medical milk commission as to 
temperature, odor, taste, and bacterial content. 

72. Fat standards. — The fat standard for certified milk shall 
be 4 per cent, with a permissible range of variation of from 3.5 
to 4.5 per cent. 

73. The fat standard for certified cream shall be not less 
than 18 per cent. 

74. If it is desired to sell higher fat-percentage milks or 
creams as certified milks or creams, the range of variation for 
such milks shall be 0.5 per cent on either side of the advertised 
percentage and the range of variations for such creams shall be 
2 per cent on either side of the advertised percentage. 

75. The fat content of certified milks and creams shall be 
determined at least once each month. 

76. The methods recommended for this purpose are the Bab- 
cock {a), the Leffmann-Beam (6), and the Gerber (c). 

(a) Babcock test. — The Babcoek test is based on the fact that strong snlphnrie 
acid will dissolve the nonfatty solid constituents of milk, and thus enable the fat to 
separate on standing. It can be conducted by any of the Babcock outfits which are 
purchasable in the market. 

''The test is made by placing in the special test bottle 18 grams (17.6 e. c.) of 
milk. To this is added, from a pipette, burette, or measuring bottle, 17.5 c. e. com- 
mercial sulphuric acid of a specific gravity of 1.82 to 1.83. The contents of the bottle 
are carefully and thoroughly mixed by a rotary motion. The mixture becomes brown 
and heat is generated. The test bottle is now placed in a properly balanced centrifuge 
and whirled for 5 minutes at a speed of from 800 to 1,200 revolutions per minute. Hot 
water is then added to fill the bottle to the lower part of the neck, after which it is again 
whirled for two minutes. Now, enough hot water is added to float the column of fat 
into the graduated portion of the neck of the bottle, and the whirling is repeated for a 
minute. The amount of fat is read while the neck of the bottle is still hot. The reading 
is from the upper limits of the meniscus. A pair of calipers is of assistance in measuring 
the column of fat." (Jensen's Milk Hygiene, Leonard Pearson's translation.) 

(&) Leffmann-Beam test. — The distinctive feature is the use of fusel oil, the effect 
of which is to produce a greater difference in surface tension between the fat and the 
liquid in which it is suspended, and thus promote its readier separation. This effect has 
been found to be heightened by the presence of a small amount of hydrochloric acid. 

The test bottles have a capacity of about 30 c. c. and are provided with a graduated 
neck, each division of which represents 9.1 per cent by weight of butter fat. 

Fifteen centimeters of the milk are measured into the bottle, 3 c. c. of a mixture 
of equal parts of amyl alcohol and strong hydrochloric acid added and mixed. Then 9 
c. c. of concentrated sulphuric acid is added in portions of about 1 c. c. ; after each 
addition the liquids are mixed by giving the bottle a gyratory motion. If the fluid has 
not lost all of its milky color by this treatment, a little more concentrated acid must 
be added. The neck of the bottle is now immediately filled at about the zero point 
with one part sulphuric acid and two parts water, well mixed just before using. Both 
the liquid in the bottle and the diluted acid must be hot. The bottle is then placed at 
once in the centrifugal machine; after rotation from one to two minutes, the fat will 
collect in the neck of the bottle and the percentage may be read off. 

(c) Gerder's test. — This test is applied as follows: The test bottles are put into, 
the stand with the mouths uppermost; then, with the pipette designed for the purpose, 
or with an automatic measurer, 10 e. e. of sulphuric acid are filled into the test bottle, care 
being taken not to allow any to come in contact with the neck. The few drops remaining 
in the tip of the pipette should not be blown out. Then 11 c. c. of milk are measured with 
the proper pipette and allowed to flow slowly onto the acid, so that the two liquids mix 
as little as possible. Finally, the amyl alcohol is added. (It is important to use the re- 
agents in the proper order, which is — sulphuric acid, milk, amyl alcohol. If the sulphuric 
acid is followed by amyl alcohol and the milk last, then the residt is sometimes incorrect.) 
A rubber stopper, which must not be damaged, is then fitted into the mouth of the test 
bottle, and the contents are well shaken, the thumb being kept on the stopper to prevent 



266 Principles of Legislative Milk Control. 

it coining out. As a considerable amount of heat is generated by the action of the 
sulphuric acid on the milk, the test bottle should be wrapjjed in a cloth. 

The shaking of the sample must be done thoroughly and quickly, and the test 
bottle inverted several times, so that the liquid in the neck becomes thoroughly mixed. 
By pressing in the rubber stopper the height of the liquid can be brought to about the 
zero j)oint on the scale. 

If only a few samples have to be analyzed an<l the room is warm, the test 
bottles can be put into tlie centrifuge without any preliminary heating, otherwise 
the test bottles must be warmed for a few minutes (not longer) in the water bath 
at a temperature of C0° to G5° C. When the temperature rises higher than this, 
say above 70° C, the rubber stopper is liable to be blown out of the test bottle. 
After the test bottles have been heated they are arranged symmetrically in the 
centrifuge and whirled for 3 to 4 minutes at a speed of about 1,000 revolutions per 
minute. When the centrifuge has a heating arrangement attached to it, the preliminary 
warming is not, of course, necessary, '\\lien the test bottles are taken out of the 
centrifuge, they are again placed in the water bath at a temperature of 60° to 65° C, 
and left there for several minutes before being read; where the centrifuge is heated, the 
tubes can be read off as taken from the centrifuge. 

By carefully screwing in the rubber stopper, or even by pressing it, the lower 
limit of the fat column is brought onto one of the main divisions of the scale, 
and then, by holding the test bottle against the light, the height of the column of 
fat can be accurately ascertained. The lowest point of the meniscus is taken as the 
level when reading the upper surface of the fat in a sample of whole milk, and the 
middle of the meniscus for separated milk. 

If the column of fat is not clear and sharply defined, the sample must be again 
whirled in the centrifuge. 

Each division on the scale is equivalent to 0.1 per cent, so it is very easy to 
read to 0.05 per cent, or, with a lens, to 0.025 per cent. If the number which is 
read off is multiplied by 0.1, then the percentage quantity of fat in the milk is obtained; 
e. g., if the number on the scale was 36.5, then the percentage of fat is 3.65. (Milk 
and Dairy Products, Barthel; translated by Goot^lvin, p. 71.) 

77. Before condemning- samples of milk which have fallen out- 
side the limits allowed, the chemist shall have determined, by 
control ether extractions, that his apparatus and his technique are 
reliable. 

78. Protein standard. — The protein standard for certified 
milk shall be 3.50 per cent, with a permissible range of variation 
of from 3 to 4 per cent, 

79. The protein standard for certified cream shall corre- 
spond to the protein standard for certified milk. 

80. The protein content shall be determined only when any 
special consideration seems to the medical milk commission to 
make it desirable. 

81. It shall be determined by the Kjeldahl method, using the 
Gunning or some other reliable modification, and employing the 
factor 6.25 in reckoning the protein from the nitrogen. 

Kjeldahl method. — Five cubic centimeters of milk are measured carefully into a 
flat-bottom 800 c. c. Jena flask, 20 c. c. of concentrated sulphuric acid (C. P. ; sp. gr., 
1.S4) are added, and 0.7 gram of mercuric oxid (or its equivalent in metallic mercury) ; 
the mixture is then heated over direct flame until it is straw-colored or perfectly 
white; a few crystals of potassium permanganate are now added till the color of the 
liquid remains green. All the nitrogen in the milk has then been converted into the 
form of ammonium sulphate. After cooling, 200 c. c. of ammonia-free distilled water 
are added, 20 c. c. of a solution of potassium sulphide (containing 40 grams sulphide 
per liter), and a fraction of a gram of powdered zinc. A quantity of semi-normal 
HCl solution more than sufficient to neutralize the ammonia obtained in the oxidation 
of the milk is now carefully measured out from a delicate burette (divided into 
1/20 e. c.) into an Erlenmeyer flask and the flask connected with a distillation appa- 
ratus. At the other end the Jena flask containing the watery solution of the ammonium 



standards for Certified Milk. 267 

sulphate is connected, after adding 50 c. c. of a concentrated soda solution (1 pound 
"pure potash" dissolved in 500 c. c. of distilled water and allowed to settle); the 
contents of the Jena flask are now heated to boiling, and the distillation is continued for 
40 minutes to an hour, until all ammonia has been distilled over. 

The excess of acid in the Erlenmeyer receiving flask is then accurately titrated 
back by means of a tenth-normal standard ammonia solution, using a cochineal solution 
as an indicator. From the amount of acid used the per cent of nitrogen is obtained; 
and from it the per cent of casein and albumen in the milk by multiplying by 6.25. 
The amount of nitrogen contained in the chemicals used is determined by blank ex- 
periments and deducted from the nitrogen obtained as described. (Farrington and Woll, 
Testing Milk and Its Products, p. 221.) 

82. Coloring matter and preservatives. — All certified milks 
and creams shall be free from adulteration, and coloring matter 
shall not be added thereto. 

83. _ Tests for the detection of added coloring matter shall 
be applied whenever the color of the milk or cream is such as to 
arouse suspicion. 

Test for coloring matter. — The presence of foreign coloring matter in milk is 
easily shown by shaking 10 c. c. of the milk with an equal quantity of ether; on 
standing, a clear ether solution will rise to the surface; if artificial coloring matter 
has been added to the milk, the solution will be yellow colored, the intensity of the 
color indicating the quantity added; natural fresh milk will give a colorless ether 
solution, (Testing Milk and Its Products, Farrington and Woll, p. 244.) 

^ 84. ^ Tests for the detection of formaldehyde, borax, and bo- 
racic acid shall be applied at least once each month. Occasionally 
application of tests for the detection of salicylic acid, benzoic acid, 
and the benzoates is also recommended. 

Test for the detection of formaldehyde. — ^Pive cubic centimeters of milk is 
measured into a white porcelain dish, and a similar quantity of water added; 10 c. c. 
of HCl, containing a trace of Fe2 Clo, is added, and the mixture is heated very 
slowly. If formaldehyde is present, a violet color will be formed. (Testing Milk 
and Its Products, Farrington and Woll, p. 249.) 

Test for horacic acid (borax, borates, preservaline, etc.). — One hundred cubic 
centimeters of milk are made alkaline with a soda or potash solution, and then evaporated 
to dryness and incinerated. The ash is dissolved in water, to which a little hydrochloric 
acid has been added, and the solution filtered. A strip of turmeric paper moistened 
with the filtrate will be colored reddish brown when dried at 100°C. on a watch glass if 
boraeic acid is present. ' 

If a little alcohol is poured over the ash to which concentrated sulphuric acid 
has been added, and fire is set to the alcohol, after a little while this will burn with 
a yellowish-green tint, especially noticeable if the ash is stirred with a glass rod 
and when the flame is about to go out. (Testing Milk and Its Products, Farrins'ton 
and Woll, p. 247.) • ^ 

Test for salicylic acid {salicylates, etc.). — Twenty cubic centimeters of milk are 
acidulated with sulphuric acid and shaken with ether; the ether solution is evaporated, 
and the residue treated with alcohol and a little iron-chlorid solution; a deep violet 
color will be obtained in the presence of salicylic acid. (Testing Milk and Its Products 
Farrington and Woll, p. 248.) ' 

Test for benzoic acid. — Two hundred and fifty to five hundred cubic centimeters 
of milk are made alkaline with a few drops of lime or baryta water, and then evaporated 
to about a quarter of the bulk. Powdered gypsum is stirred into the remaining liquid 
until a paste is formed, which is then dried on the water bath. The gypsum only 
serves to hasten the drying, and powdered pumice stone or sand can be lised equally 
well. When the mass is dry, it is finely powdered and moistened with dilute sulphuric 
acid and shaken out three or four times with about twice the volume of 50 per cent 
alcohol, in which benzoic acid is easily soluble in the cold, the fat only being dissolved to 
a very slight extent or not at all. The acid alcoholic liquid from 'the various extrac- 
tions, which contains milk sugar and inorganic salts in addition to the benzoic acid 
is neutralized with baryta water and evaporated to a small bulk. Dilute sulphuric acid 



0(5g Principles of Legislative Milk Control. 

is again added, and the liquid shaken out with small quantities of ether. On evapora- 
tion of the ether, the benzoic acid is left behind in almost pure state, the only impuri- 
ties being small (|uantitics of fat or ash. 

The benzoic acid which is ol)tained is dissolved in a small quantity of warm 
water, a drop of sodium acetate and neutral ferric chloride added, and the red precipitate 
of benzoate of iron indicates the presence of the acid. (Milk and Dairy Products, Bar- 
thel; translated by Goodwin, p. 121.) 

85. Defection of heated milk. — Certified milk or cream shall 
not be subjected to heat unless specially directed by the commis- 
sion to meet emergencies. 

8(5. Tests to determine whether such milks and creams have 
been subjected to heat shall be applied at least once each month. 

Detection of heated mill'. — Storch's method. — Five cubic centimeters of milk are 
poured into a test tube; a drop of weak solution of hydrogen dioxide (about 0.2 per 
cent) which contains about 0.1 per cent sulphuric acid, is added, and two drops of a 
2 per cent solution of paraphenylendiamin (solution should be renewed quite often), 
then the fluid is shaken. If the milk or the cream becomes, at once, indigo Idue, or the 
whey violet or reddish brown, then this has not been heated or, at all events, it has not 
been heated higher than 78° C. (172.5° F.); if the milk becomes a light bluish gray 
immediately or in the course of half a minute, then it has been heated to 79° to 80° C. 
(174.2° to 176° F.). If the color remains white, tlie milk has been heated at least to 80° 
C. (176° F.). In the examination of sour milk or sour buttermilk, lime water must be 
added, as the color reaction is not shown in acid solution. 

Arnold's guaiac method. — A little milk is poured into a test tube and a little 
tincture of guaiac is added, drop by drop. If the milk has not been heated to 80° C. 
(176° F.) a blue zone is formed between the two fluids; heated milk gives no reaction, 
but remains white. The guaiac tincture should not be used perfectly fresh, but shoubl 
have stood a few days and its potency have been determined. Thereafter it can be 
used indefinitely. These tests for heated milk are only active in the case of milks 
which have been heated to 176° F. or 80° C. (Jensen's Milk Hygiene, Pearson's transla- 
tion, p. 102.) 

Mieroscopic test for heated {pasteurised) mill' — Frost and Eavenel. — About 15 c. e. 
of milk are centrifuged for 5 minutes, or long enough to throw down the leucocytes. 
The cream layer is then completely removed with absorbent cotton and the milk drawn 
off with a pipette, or a fine-pointed tube attached to a Chapman air pump. Only 
about 2 mm. of milk are left above the sediment which is in the bottom of the sedimen- 
tation tube. 

The stain, which is an aqueous solution of safranin 0, soluble in water, is then 
added very slowly from an opsonizing pipette. The important thing is to mix stain and 
milk so slowly that clotting does not take place. The stain is added until a deep 
opaque rose color is obtained. After standing o minutes, by means of the opsonizing 
pipette, which has been washed out in hot water, the stained sediment is then transferred 
to slides. A small drop is placed at the end of each of several slides and spread by 
means of a glass spreader, as in Wright's method for opsonic index determinations. 

In an unheated milk the polymorphonuclear leucocytes have their protoplasm 
slightly tinged or are unstained. 

In heated milk the polymoT-phonnclear leucocytes have their nuclei stained. In 
milk heated to 6v3° C. or above, practically all of the leucocytes have their nuclei 
definitely stained. When milk is heated at a lower temperature the nuclei are not all 
stained above 60° C. The majority, however, are stained. 

87. Specific rjravify. — The specific ^ravitv of certified milk 
shall rano-e from 1.029 to 1.034. 

SS. The specific gravity shall be determined at least each 
month. 

The Quevenne lactodensimeter is recommended for the determination of the specific 
gravity. It is made like an ordinary aerometer and divided into degrees which cori-es- 
pond to a specific gravity from 1.014 to 1.040, or only 1.022 to 1.038, since by the latter 
division a greater space is gained between the different degrees without unduly lengthen- 
ing the instrument. From such a lactodensimeter one can easily read off" four decimal 
l)laces. 



Standards for Certified Milk. 269 

The milk the specific gravity of which is to be determined is well shaken and poured 
into a high glass cylinder of suitable diameter; the aerometer is dropped in slowly, in 
order to prevent its bobbing up and down. (The bulb should be free from adhering 
air bubbles.) The figures on the stem are the second and third decimals of the numbers 
of the specific gravity, so that 34 is to be read 1.034. For this examination, the tempera- 
ture of the milk must be 15° C. (60° F.) ; if it is not, the specific gravity of the milk 
at 15° C. must be calculated from the specific gravity found and from the temperature, 
for in milk inspection and analysis this is the standard. 

Methods and Regulations for the Medical Examination of 
Employees^Their Health and Personal Hygiene. 

89. A medical officer, known as the attending dairy physi- 
cian, shall be selected by the commission, who -should reside near 
the dairy producing certified milk. He shall be a physician in 
good standing and authorized by law to practice medicine; he 
shall be responsible to the commission and subject to its direction. 
In case more than one dairy is under the control of the commis- 
sion and they are in different localities, a separate physician should 
be designated for employment for the supervision of each dairy. 

90. Before any person shall come on the premises to live 
and remain as an employee, such person, before being engaged 
in milking or the handling of milk, shall be subjected to a complete 
physical examination by the attending physician. No person shall 
be employed who has not been vaccinated recently or who upon 
examination is found to have a sore throat, or to be suffering from 
any form of tuberculosis, venereal disease, conjunctivities, di- 
arrhea, dysentery, or who has recently had typhoid fever or is 
proved to be a typhoid carrier, or who has any inflammatory dis- 
ease of the respiratory tract, or any suppurative process or infec- 
tious skin eruption, or any disease of an infectious or contagious 
nature, or who has recently been associated with children sick 
with contagious disease. 

9L In addition to ordinary habits of personal cleanliness 
all milkers shall have well-trimmed hair, wear close-fitting caps, 
and have clean shaven faces. 

^ 92. When the milkers live upon the premises their dormi- 
tories shall be constructed and operated according to plans ap- 
proved by the commission. A separate bed shall be provided for 
each milker and each bed shall be kept supplied with clean bed- 
clothes. Proper bathing facilities shall be provided for all em- 
ployees on the dairy premises, preferably a shower bath, and 
frequent bathing shall be enjoined. 

93. In case the employees live on the dairy premises a suit- 
able building shall be provided to be used for 'the isolation and 
quarantine of persons under suspicion of having a contagious 
disease. 

The following plan of construction is recommended : 

The quarantine building and hospital should be one story high and contain at 
least two rooms, each with a capacity of about 6,000 cubic feet and containing not 
more than three beds each, the rooms to be separated by a closed partition. The doors 



Fiff. 27. 




A practical, coiivenieTit, sanitary stable. 
(Photo by Dr. Cassius Way.) 



Fiof. 28. 




A well lighted, well ventilated dairy barn. 
(Photo by Dr. Cassius Way.) 



standards for Certified Milk. 271 

opening into the rooms should be on opposite sides of the building and provided with 
locks. The windows sliould be barred and the sash should be at least .5 feet from the 
ground and constructed for proper ventilation. The walls should be of a material 
ohieh will allow proper disinfection. The floor should be of painted or washable wood, 
preferably of concrete, and so constructed that the floor may be flushed and properly 
disinfected. Proper heating, lighting, and ventilating facilities should be provided. 

94. In the event of any illness of a suspicions nature the 
attending physician shall immediately quarantine the suspect, 
notify the health authorities and the secretary of the commission, 
and examine each member of the dairy force, and in every inflam- 
matory affection of the nose or throat occurring among the 
employees of the dairy, in addition to carrying out 'the above- 
mentioned program, the attending physician shall take a culture 
and have it examined at once by a competent bacteriologist ap- 
proved by the commission. Pending such examination, the affected 
employee or employees shall be quarantined. 

95. It shall be the duty of the secretary, on receiving notice 
of any suspicious or contagious disease at the dairy, at once to 
notify the committee having in charge the medical supervision of 
employees of the dairy farm upon which such disease has de- 
veloped. On receipt of the notice this committee shall assume 
charge of the matter, and shall have power to act for the com- 
mission as its judgment dictates. As soon as possible thereafter, 
the committee shall notify the commission, through its secretary, 
that a special meeting may be called for ultimate consideration 
and action. 

96. When a case of contagious disease is found among the 
employees of a dairy producing certified milk under the control 
of a medical milk commission, such employee shall be at once 
quarantined and as soon as possible removed from the plant, and 
the premises fumigated. 

When a case of contagion is found on a certified dairy it is advised that a 
printed notice of the facts shall be sent to every householder using the milk, giving 
in detail the precautions taken by the dairyman under the direction of the commission, 
and it is further advised that all milk produced at such dairy shall be heated at 145° F. 
for 40 minutes, or 155° F. for 30 minutes, or 167° F. for 20 minutes, and immediately 
cooled to 50° F. These facts should also be part of the notice, and such heating of 
the milk should be continued during the accepted period of incubation for such con- 
tagious disease. 

The following method of fumigation is recommended : 

After all windows and doors are closed and the cracks sealed by strips of paper 
applied with flour paste, and the various articles in the room so hung or placed as to be 
exposed on all sides, preparations should be made to generate formaldehyde gas by 
the use of 20 ounces of formaldehyde and 10 ounces of permanganate of potash for 
every 1,000 cubic feet of space to be disinfected. 

For mixing the formaldehyde and potassium permanganate a large galvanized- 
iron pail or cylinder holding at least 20 quarts and having a flared top should be used 
for mixing therein 20 ounces of formaldehyde and 10 ounces of permanganate. A 
cylinder at least 5 feet high is suggested. The containers should be placed about in 
the rooms and the necessary quantity of permanganate weighed and placed in them. 
The formadehyde solution for each pail should then be measured into a widemouthed 
cup and placed by the pail in which it is to be used. 

Although the reaction takes place quickly, by making preparations as ad\dsed all 
of the pails can be "set off" promptly by one person, since there is nothing, to do 
but pour the formaldehyde solution over the permanganate. The rooms should be 



272 Principles of Legislative Milk Control. 

kejjt closeil for four hours. As there is a slight danger of fire, the reaction should be 
watched through a window or the pails placed on a noninflammable surface. 

97. Following a weekly medical inspection of the employees, 
a montlil.y report shall be snl)mitted to the secretary of the medical 
milk commission, on the same recurring date hy the examining 
visiting physician. 

The following schedule, filled out in writing and signed by liinisolf, is recommended 
as a suitable form for the attending ])iiysieian 's report: 

This is to certify that, on the dates below indicated, official visits were made to 

the dairy, owned and conducted by of (indicating town and 

State), where careful inspoctions of tiie dairy employees weie made. 

(a) Number and dates of visits since last report. . 

(&) Number of men employed on the jdant. . 

(c) Has a recent epidemic of contagion occurred near the dairy, and what 
was its nature and extent? . 

(d) Have any cases of contagious or infectious disease occurred among the 
men since the last report? . 

(e) Disposition of such cases. 

(/) What individual sickness has occurred among the men since the last 
report '? 



(fj) Disposition of such cases. . 

(7() Numlier of employees now quarantined for sickness. . 

(i) Describe the personal hygiene of the men employed for milking when pre- 
pared for and during the pi'ocess of milking. . 

(.?') What facilities are provided for sickness in employees? . 

(I') General hygienic condition of the dormitories or houses of the em- 
ployees. 



(?) Suggestions for improvement. . 

(m) What is the hygienic condition of the employees and their surroundings? 



(?0 How many employees were examined at each of the foregoing visits? 
(o) Eemarks. 



Date, 



Attending Physician. 



Fig. 29. 




fM- 



Make 



AN EFFICIENT VENTILATING SYSTEM. 

Perspective view of one center vent of barn, showing relation of ventilator to the hay fork, the 
timbers of the barn, the butter, and the relation of the fresh air intakes to the foul air 
out-take or ventilator. The outlet chute should be built on the ratio of 5 or 6 cows to the 
square foot. There should be enough intakes about one-half square foot in area evenly dis- 
tributed around the outside of the stable to nearly equal the area of the outlet shaft. There 
should be four square feet of window area per cow. Slide A can be adjusted to regulate the 
size of the opening in accordance with the temperature of the barn. This system is practical, 
inexpensive and will work absolutely perfect. 



18 



INDEX 



A PAGE 

Abortion, influence on lactation ... 67 

Acidbutyrometric test 227 

Acid coagulation . 34 

Acidity, degree of 

66, 71, 81, 185, 189, 214 

Ackermann's Slide-ruler 229 

Aetinobacillosis 131 

Actinomyces 131, 170 

Actinomycosis 8, 83, 130 

Actinophytes 170 

Action of bacteria 152 

Action of freezing 42 

Action of heating 193 

Activity of the udder. .12, 16, 22, 59 
Adjusted milk, requirements for. . 243 
Administration, equipment for 

milk control 236 

Aeration 149 

Aerobic 157 

Aerogenes 27, 82, 166 

Age, influence on lactation 65 

Age of milk 191 

Agressins 53 

Albumin 33, 38, 57, 193 

Albuminophores 29 

Alcoholic ferment 170 

Alcohol in milk 138 

Alcohol test 80, 214 

Alimentary infection in tubercu- 
losis 107, 108 

Alizarol test 80, 214 

Alkalinity 80, 215 

Aloes excreted by milk 138 

Amboceptor 49, 221 

Amylase 46, 82, 218 

Amyloid bodies 29 

Anaerobic 157 

Anaphylaxis 57 

Anatomical 1 

Anthrax 74 

Antibodies 45, 54 

Antigen 45, 55 

Antipyrin 138 

Antirennet 37 

Antisubstances 45, 54 

Aphthous fever 198 

Aplasia 3 

Appearance of milk 40, 71, 77 

Apomorphin 139 

Apparatus for pasteurization .... 195 



PAGE 

Arsenic 52 

Ash contents 40, 80 

Atrophy of the udder 13 

Atrophin 139 

B 

Babcoek test 228 

Bacteria, action of 152 

Bacteria, counting of . . .153, 156, 224 

Bacteria in market milk 82, 152 

Bacteria in milk, laboratory ex- 
aminations 239 

Bacteria in milk, standards of... 238 

Bacterial catalase 187 

Bacteria, thermal death point of. 197 

Bactericidal action of milk 158 

Bang's method of eradicating- tu- 
berculosis 118 

Basis of the mammary gland. ... 9 

Basket cells 10 

Bedding 144 

Bioplasts 12 

Bitter milk 137, 175 

Blackleg- 169 

Blue milk 137, 178 

Boiling milk 193 

Boraeic acid 138 

Botryomycosis 8, 130 

Bottling plants for milk 249 

Botulism 169 

Bovo-vaeeination 116 

Bradsot 169 

Breeds, influence of 62 

Breeds, milk yield of various .... 62 

Brewer's grains 140 

Bright light, protection from.... 149- 

Bromine 138 

Brown milk 178 

Buddesation 199 

Buttermilk 171, 243 

Butyric acid bacilli. 158, 163, 168, 169 
Butyrometer 227 

C 

Calculation of milk solids 229 

Cans 149 

Caps 27, 29 

Carbonization of milk 202 

Casease bacteria 162, 167 



275 



27G 



Imlex. 



PAGE 

Casein :33, Kil 

Catalase 47. SI, 1S7 

Catalase test 217 

Catarrh of the udch'r (5, 15 

Causes of inHainnuUion 3 

Cell liiuno- 10 

Cells in inflaniniatioii 1") 

Cells in the colostra! stasie .... 9 

Cells of the external skin S, 24 

Cells of the teats 9, 24 

Cells of the tissues 9, 32 

Centrifusializatidii 1 ")0 

Centrifuge slime loO 

Certified' milk standards 2o(i, 271 

Chauji'es in internal diseases .... OS 

Chanijes in taste 70 

Changes of cell forms 10, 11 

Chansies of the udder 9 

Cheese bacteria I(i2, 167 

Chemical characteristics 32, 02 

Chemical standards for milk 

products 240, 243 

Chemical substances, adulteration 

with 198 

Cholera 192 

Chloride of calcium serum.... 44, 232 

Chloroform 13S 

Chromatolysis 28 

Chronic mastitis 15 

Cistern 2, 8, 25 

Cistern, mucous membrane of. .9, 25 

Climaterie 19 

Closino- of cans 150 

Coaii'ulation 165, 183 

Coition, influence of 67 

Colibacillosis 5 

Color spots in milk 179, 213 

Colon bacilli 5, 52 

Colostrum 65 

Colostral cells 26 

Colostral milk 39, 65 

Colostral period 66 

Complement 49, 51 

Complement test 221 

Complete milking' 145 

Composition of milk 32, 62 

Conception 10 

Concrements 31 

Conductibility of milk 42 

Conformation of milk animals. . . 64 

Construction of stable 142 

Consumption of milk per capita. 203 
Contamination with disease pi'o- 

ducers 68 

Content values in milk 41 

Contraction of the milk 12 

Control of the milk supply. .203, 233 



Cooperative creameries 210 

Copi)er 138 

Cori)ora amylacoa 30 

(^ountins' bacteria. 224 

Cows, requirements for 246 

Cow stables, re(|uirements for. . . . 246 

Cream and milk, homoiienized. . . 243 
Cream, chemical standard for . . . .243 

Cream classification 242 

Cream, foi'mation of 41 

Ci'eam, laboratoiy standard for. . 250 

Cream, pasteurized, standard for. 255 
Cream production, requii'ements 

for 250 

Currvinsi', effect of 140 

Cutis 1, 27 

Cylindrical epithelia 8 

D 

Daily cows, requirements and rec- 
ommendations 246 

Dairy employees, medical inspec- 
tion of 241 

Dairy farms, inspection of 252 

Dairy utensils, requirements for.. 247 
Dealers, milk, licenses and permits 

for 245 

Decomposition phases 161 

Defects of milk 175, 181, 226 

Defeneration of cells 11, 15 

Desquamation of epithelial cells. . 12 
Development of mammary gland 

1, 2, 16 

Diagnosis of mastitis 93, 221, 222 

Diastase 46, 81 

Differences in types of tubercle 

bacilli .' 103 

Diminution of bacterial content. . 160 

Diphtheria from milk 192 

Dirt content 215 

Dirty milk 182 

Diseases, influence on quality G7 

Disease in milk, duty of health 

officials '. 234 

Diseases of man caused bv milk. . 

'. . . 128. 191 

Diseases of the udder. . .4, 77, 80, 125 

Disease producers 67 

Disting'uishino' the milk from va- 
rious species of animals 55 

Drains 144 

Drinking- Avater, effect of 135 

Drugs, effect of 138 

Dry animal » 48 

Dry period 67 

Dry solids 41, 63 



Index. 



277 



E PAGE 

Ecto-ferments 46 

Effects of pasteurization 196 

Electrical sterilization 202 

Elimination of toxin 54, 128 

Elimination of tubercle bacilli . . . 103 

Embiyo, action of the 18, 21 

Embryonic impulses 21 

Employees, dairy, medical inspec- 
tion of 241 

Employees of dairies, require- 
ments for 247 

Endoferments 46 

Equations for calculating adul- 
terations 42 

Epithelia in milk 26 

Erythrocytes 27, 66 

Estrum 67 

Estrum influence on lactation .... 67 

Ether, passing- into milk 138 

Examination of milk 212 

Exercise, effect of 140 

External skin of teats 8 



F 

Farms, dairy, sanitary inspection 

of 252 

Farrow 67 

Fat 33, 63, 80 

Fat content 41, 77, 146 

Fat free solids 42, 77, 229 

Fat splitting bacteria 170, 177 

Fatty acids in butter 134 

Feed, effect of, on fat 133 

Feed, effect of, on yield 133 

Feeding, influences of 132 

Fermentation test 183, 219 

Fermented milk 171 

Ferments 45, 81 

Filling of the udder 22, 69 

First drawn milk 48 

Fishy milk 137, 176 

Fisting 58 

Flash process 198 

Flow of milk 22 

Foam cells 25 

Foot and mouth disease . . . 71, 73, 198 

Foreign substances in milk 69 

Formaldehyde as a preservative. . 

200, 211, 217 

Formalin methylen blue . .48, 82, 187 
Formulas for adulterations ...... 230 

Free nuclei 28 

Freezing of milk 42, 149 

Fresh milking animals 48, 51 

Function of the udder. ....... .9, 12 



G ■ PAGE 

Galactase 46 

Galactoenzyme 46 

Gait, yellow 80, 96 

Garget, yellow 80, 96 

Garlicky taste 137 

Gaseous phlegmons 169 

Gases 33, 40 

Gerber's acidbutyrometric test. . . . 227 

Germicidal properties 159, 161 

Giant udder 3 

Gioddu 174 

Globules, milk globules 24, 43 

Globules, Niessen's 29 

Globulin 38, 193 

Grading of milk 236, 241 

Guaranteed milk, requirements of. 244 



Haptophore 49 

Health authorities and disease in 

milk 234 

Hegelund's method of milking. 59, 146 

Hematogenic influences 4, 17 

Hemorrhages . '. 4, 74 

Henkel-Soxhlet test 214 

Hepin 200 

Hepin catalase 199 

Heredity in production 64 

Hormones 17 

Hoyberg's test 215 

Hygienic importance of mastitis. . 

85, 102, 125, 127, 129 

Hyperemia of the udder 4 

Hypertrophy of the udder 3 

Hypoplasia of the udder 3 



Immune substances 45, 48 

Inactivity of the udder. .9, 13, 15, 26 

Indirect oxydase 46 

Infection of milk with eoli-typhus 

group 126 

Inflammation, causes of ....... . 4 

Inflammation, diagnosis of .... 6, 15 

Inflammation of the udder 4 

Influence of cooling 156 

Influences affecting quality of 

milk \ * 62 

Influences, effect of external 132 

Influences, effect of internal. . .25, 62 
Inspection of dairy employees... 241 
Intermittent stimulation of milk- 
ing _. 25, 58 

Intermittent stimulation of suck- 
ing 58 

Internal influences on the char- 
acter of milk 25, 62 



278 



Index. 



PAGE 

InteiTui»t('(l inilkiiiii' 39 

Intestinal intlamniations, inlln- 

enoes of <>i^ 

Iron l->''^ 



Kefir 172 

Kneadinsi' (see Methods of milk- 
in-) .' 25, fiS 

KoclTs London statement 10.") 

Knniys l~-4 



230 

250 
4G 

.IG 
02 
39 
21 

IGG 
3S 

220 
3,S 
38 
41 
40 
55 



Labolinp,' and dating' milk 23S 

Lal)oi'atory examinations for bac- 
teria 

Laboratory standards for milk 

and oi'eam 

Lactase (see Enzymes) 

Lactation, connnencins' of 

Lactation, inllnences on 17, 

Lactation, periods of 10, 

Lactation, snstaininji- of 

Lactic acid producers 103, 

Lactoalbnmin 

Lactodensimeter 

Lactoglobulin 

Lacto-raucin 

Lactoscope 

Lactose 

Lactoserum 

Laws g'overnin.o' milk production . 235 

Lead compounds in milk 13S 

Lecithin 194 

Legislative control of milk 233 

Leucocytes 15, 27, OG, 94, 223 

Leucocytic test 24, 222 

Licenses and permits for milk 

dealers 241, 245 

Light 142 

Local stimulants of the milk 

gland IS, 21, 5S 

Lymph vessels 3 

Lymphocytes 27 

M 

l\Lalignant edema 109 

IMalta fever 70, 198 

IMammaiy gland, activity of .... 145 
Mammary gland, development of 1 
Mammary gland, structure of... 8 

Manmiary region 1 

Manure, disposal of 144 

Maiket milk, standards for 250 

:Mastitis 5, 77, 125, 1.30 

]\Iedicinal agents 137 

]\Iedicinal inspection of employees 241 
Mercury .'. . . 138 



P.\GE 

Mesophiles 158 

IMethods for i)rocunng sterile milk 154 

Methvlene blue reductase 48 

Metritis 68 

Micrococcus melitensis 70 

Microscopic examination of milk 240 

Microscopy of milk 24 

Milk, adjusted, requirements of. . 243 

Milk analyses, publicity for 241 

Milk and cream homogenized . . . 243 
Milk and cream jnistenrized .... 255 
Milk, certified, standard require- 
ments 250, 271 

]\rilk, chemical standards for.. 240, 243 

Milk classification 2.30, 241 

]\Iilk constif nents. origin of... 32, 38 
Milk Control, administrative .... 236 
Milk control, fundamental princi- 
ples of 233, 271 

]\[ilk control in IMunich 200 

Milk control, need of 2.34 

Milk control, standard rules for. 235 

Milk dealers, licenses for 245 

Milk defects 226 

Milk, diseases transmitted by.... 191 

Milk duct 9, 25 

Milk fat 37 

Milk flow 22 

Milk formation 17, 22 

Milk for joasteurization, require- 
ments of 254 

Milk globules 24, .38, 43 

Milk, grading of 236, 241, 242 

Milk, handling of 248 

Milking, complete 145 

Milking, methods of 58 

Milk, injurious effects caused by. 128 

Milk inspection 211 

Milk in stores 249, 254 

Milk, labeling and dating of 238 

Milk, laboratory examination of. . 239 
Milk, market, sale luider guarantee 244 

Milk, market, standards for 250 

Milk, microscopic examination of 240 

]\rilk, mislabeling of 241 

Milk pails 147 

Milk, pasteurization of 237 

Milk plants, inspection of 251 

Milk plasma 24, 33 

Milk producing substances 18 

Milk production, effect of feeding 

on 45 

Milk production, legal require- 
ments of 235 

Milk, i>us in 15 

Milk, raw, standards for 246 

Milk ridge 1 

Milk room, requirements for .... 246 



Index. 



279 



PAGE 

Milk secretion 146 

Milk serum 33 

Milk sickness 75 

Milk, skim, chemical standards of 243 
Milk, standards for bacteria in . . . 238 

Milk stosis 15, 48 

Milk, subnormal, requirements for 250 

Milk sugar 33, 40 

Milk vein 3 

Milk wells 65 

Mucin 38 

N 

Necrosis bacillus 131 

Nephritis, influence on milk pro- 
duction 69 

Nerves 3, 16 

Nervous irritation. 16 

Niessen's globules 29 

Nitrates and nitrites 232 

Nuclei 28 

Nuclei, free 28 

Nutritive substances, theory of . . . 17 



CEdema of the udder 4 

■Official inspection 206, 209, 211 

Offspring, nutritive producing 

substances 18 

Oidium lactis 168, 170 

Opsonins 52 

Organization of control 206, 209 

Original ferments 46, 187, 194 

Origin of milk constituents . . . 33, 38 
Ostertag's method of tuberculosis 

eradication 121 

Over extending the time of milking 48 

Oxydase 46 

Ozonization 202 

P 

Paratyphoid fever from milk. . . . 192 
Paratyphoid group (see also In- 
flammation) 5 

Parenchyma 11 

Parenchymatous mastitis 5 

Passing of foreign substances into 

the milk 69 

Pasteurization 193, 198, 237 

Pasteurization, temperatures for. . 237 
Pasteurized milk and cream, stand- 
ards for ...253, 255 

Pasteuiizing plants 254 

Pasture milk 134 

Pathological products in milk. 68, 74 

Pathology of the udder 15 

Pavement epithelium 8 



PAGE 

Peptonizing bacteria 162 

Period between births 66 

Period of incubation 159 

Periods of lactation 16, 39, 65 

Permits for milk dealers 245 

Peroxide of hydrogen as a pre- 
servative 199 

Peroxydase 47 

Phases of decomposition 161 

Phases of development of the ud- 
der 1, 10, 16 

Phases of milk formation 22 

Physical characteristics 16, 40 

Pioscope 41 

Plant rennet 38 

Plants affecting milk 137 

Polarization of sei'um 43 

Pox 70 

Precipitation, differentiation by. . 55 

Precipitation, specific 55 

Pregnancy 17, 66 

Pregnancy impulse 17 

Pregnancy, substances of 17 

Pressure of the secretion 22 

Principal constituents 33 

Procurement of milk 58 

Production 17 

Production, diminishing of 

13, l8, 22, 58, 67 

Production, influences of heredity 63 
Production of the milk gland. . . . 

.^.17, 58, 63 

Protective substances of the body 48 

Proteids 33 

Psychrophile 157 

Puberty 10 

Publicity for milk analyses 241 

Putrefactive bacteria 163 

Putrid milk 176 

Pyknometer 227 

Pyobacillosis 82 

Q 

Quantitative and qualitative stimu- 
lants 17 

R 

Rabies 75 

Raw milk, standards for 243 

Receptors 19 

Recoveiy from mastitis 15 

Red blood cells 27, 66 

Red milk 137, 179 

Reductase 48 

Reductase test 184, 216 

Reduction number 186 

Reduction of bacterial content. . . 155 

Reduction properties , . . . 185 



280 



Index. 



PA(;E 

Reflexes on the genitals l(i, (il 

Refraction 4;i 

Regulation for milk control 2.'>5 

Rennet 37 

Rennet action 35 

Rennet action on cooked milk. . . . 3(i 

Rennet, fermentation test 220 

Rennet, inhibition 37 

Rennet, inhibitory test 220 

Resting' of the udder. i), 13. 14. 1.'). 2() 

Retaining- of milk secretion 21 

Retrogression of the udder. . . .13. 44 

Rothenfuss reagent 219 

S 

Salts 33, 40 

Salts, effects of feeding 135 

Salvarsan r)2 

Samples, collection of 211 

Sanitary inspection of dairies. 251, 252 

Scarlet fever from milk 192 

Schardinger's ferment 48 

Schardinger's test 217 

Score card for dairy 252 

Secretion, impulses of 16, 20 

Secretion, in climacterium 10 

Secretion, nerves of 3, IG, 22 

Secretion of male animals 19 

Secretion of newly borns 19 

Secretion of the udder ...16, 22, 59 

Secretion of virgin animals . .19, 20 

Secretion, retention of 22 

Secretion, stimulation of 10, 23 

Sedimentation test 51, 222 

Sediment in milk 92, 96 

Separator slime 150 

Serum 33, 38, 55 

Shell 25 

Skim milk, standards for. .. .243, 253 

Skinlets 25 

Slimy milk 179 

Soapy milk 157, 176 

Sore throat, epidemic 86, 235 

Sour milk 171 

Spaying, influence of 67 

Specific gravity of milk. . .41, 43, 226 

Sphincter 2 

Spoiled food, effects of 136 

Stable inspection 208 

Stabling 141, 246 

Stalls 143 

Standards, bacterial, for milk . . . 238 
Standards, chemical, for milk... 

240, 243 

Standards for certified milk. .256, 271 

Standards for raw milk 246 

Standards, laboratory 250 

Staphylococci in milli 12!), 168 



Starvation 

Stasis, blood 

Stasis, milk 

Sterile milk '. . . . 

Sterilization 

Sterilization by chemical sub- 
stances 

Sterilization l)y electricity 

Sterilization by heat 

Sterilization by ozonization 

Sterilization by iiltra violet I'ays. 

Stinuilation of the secretion 

16, 17, 18, 

Slinuilins 

Straining milk 

Streak milking 

Streptococci (see also Mastitis; 
also Slimy milk) .5, 88, 

Streptococcic mastitis 

Streptococcic mastitis, spread of. 

Streptococcic mastitis, importance 
of 

Streptococci of animal origin. . . . 

Stringy milk 

Stripping- 

Structure of the tissue 

Structure of the udder 

Subnormal milk, requirements for 

Sucking', stimulation of 

Sugar 

Supei'oxydase 

Supervision of production 

Surface tension 



133 

4 

48 

153 

lf)3 

201 
202 
li)3 
202 
200 



58 

17 

148 

59 

164 

82 

84 

85 
90 

179 

59 

8 

8 

250 
58 
40 
47 

209 
43 



Tatmjolk 174 

Tartar emetic 138 

Taste of milk in disease 70 

Tauruman 116 

Teat 1, 2, 25 

Teat duct 2 

Teat wall 7, 8 

Temperature for pasteurization . . 237 

Tetanus 54, 169 

Thermal death j^oint of bacteria. 197 

Thermal limits of bacteria 157 

Thermophiles 158 

Throat infections transmitted by 

milk ". 235 

Time rule for coagulation 36 

Tipping- 58 

Total fTolids 41, 63 

Toxins 49, 53 

Toxin, elimination of 54 

Trommsdorff's test 51, 95, 222 

Troughs, drain 144 

Troughs, feeding 144 



Index. 



281 



224 



97 



Tubercle bacilli, a typical 105 

Tubercle bacilli, danaer to man 

from .103, 108, 112, 114 

Tubercle bacilli, elimination of. . 103 

Tubercle bacilli in milk 

99, 100, 101, 103 

Tubercle bacilli, types of 103 

Tubercle bacilli, stability of 104 

Tubercle bacilli, virulence of. 103, 106 

Tubercle bacilli, stain for 223 

Tubercle bacilli, thermal death 

point of 197 

Tuberculosis 98, 192 

Tuberculosis, animal inoculations 

for 

Tuberculosis, appearance of milk 

in 

Tuberculosis, Bang's method of 

controlling' 118 

Tuberculosis, contamination of 

milk in 101 

Tuberculosis control work, results 

of ..123 

Tuberculosis, curative measures in 115 
Tuberculosis, dangers from bo- 
vine ^; Ill, 112, 114 

Tuberculosis immunization 116 

Tuberculosis in children, bovine 

type of 109, 112, 114 

Tuberculosis, methods of eradicat- 
ing lis 

Tuberculosis of cattle in the United 

States .^. 99 

Tuberculosis of udder 97, 99 

Tuberculosis, open 102 

Tuberculosis, Ostertag's method of 

eradicating 121 

Tuberculosis through ingestion . . . 

107, 108 

Tuberculosis, Siedamgrotzky's 

method of eradicating" 121 



PAGE 

Tuberculosis, Ujhelyi's method of 

eradicating 122 

Tuberculosis vaccination 117 

Tuberculosis verrucosa cutis .... 113 

Typhoid fever bacilli 197 

Typhoid fever from milk 191 

U 

Udder, activity of the .12, 16, 22, 59 
Udder, anatomical structure of . . 2 
Udder, changes in mastitis 

6, 79, 97, 125 

Udder, development of 1 

Udder, filling of the 22, 59 

Udder, function of the 9 

Udder, inflammation of 5, 225 

Udder, pathological changes of 

the .' ^....3, 15 

Udder, secretion of the. . .16, 22, 59 

Udder, structure of 8 

Uniceptors 48 

Utensils, requirements for 247 

V 

Ventilation 142 

Violet rays as a preservative .... 200 

Virgin individuals 9, 10 

Virgin udder 2, 9, 19 

Viscosity 43 

W 

Weather, effects of 140 

Whey, long- 180 

Whiteness, for establishing the 

quantity of fat . 41 

Witches milk 19 

Work, influence of 140 

Y 

Yeasts 170 

Yellow milk 137, 179 

Yoghurt 171 



